In 2025, the world’s cleanest countries are not just global leaders in environmental health—they are also innovators in climate policy, renewable energy, and sustainable development. These nations have earned top rankings through rigorous assessment by the Environmental Performance Index (EPI) and the Climate Change Performance Index (CCPI), which together provide the most authoritative and data-driven evaluations of national environmental performance.

The EPI, developed by Yale and Columbia Universities, uses 58 indicators across 11 categories—ranging from air and water quality to biodiversity and climate policy—to rank 180 countries on how well they meet sustainability targets. The CCPI, meanwhile, evaluates 63 countries and the EU, covering over 90% of global greenhouse gas emissions, and assesses performance in GHG emissions, renewable energy, energy use, and climate policy.

These indices are vital tools for policymakers, businesses, and communities, offering a granular view of each country’s strengths and weaknesses, helping to set targets, track trends, and identify best practices for a sustainable future. High-ranking countries benefit from advanced regulatory frameworks, greener infrastructure, and new market opportunities for sustainable technologies. Here’s a closer look at what sets each of the top 10 apart in 2025:

1. Estonia (EPI Score: 75.3)

Estonia leads the world in cleanliness and sustainability, thanks to its extensive forest cover, effective use of bioenergy, and a strong focus on natural resource management. The country has set ambitious climate goals, including a 70% reduction in greenhouse gas emissions by 2030 and carbon neutrality by 2050.

Estonia achieved an 11.3% emissions reduction in late 2024, outpacing the rest of the EU, even as its economy grew. The capital, Tallinn, has become a beacon of urban sustainability, winning the ITB Earth Award 2025 for its zero-waste Song and Dance Celebration, which drastically cut single-use plastics and promoted circular economy practices.

Estonia’s environmental policies have also led to Europe’s cleanest air and ongoing investments in wind, solar, and energy storage. However, the country faces challenges in fully phasing out fossil fuels and balancing biomass production with forest conservation.

2. Luxembourg (EPI Score: 75.0)

Luxembourg stands out as a small nation with outsized environmental achievements, earning an EPI score of 75.0 in 2024 and a 4.1-point rise over the past decade. The country leads the world in water management, boasting a near-perfect score of 90.6 in Water Resources and an astounding 99.8 in Sanitation & Drinking Water. Over 55% of Luxembourg’s land is protected, contributing to a top-tier biodiversity score of 84.8.

The nation’s capital has pioneered green investments, while advanced wastewater treatment and strict EU-aligned standards keep pollution low. While Luxembourg excels in ecosystem vitality and heavy metal pollution control, it continues to work on reducing per capita greenhouse gas emissions and curbing tree cover loss.

3. Germany (EPI Score: 74.6)

Germany ranks third globally with an EPI score of 74.6 in 2024, marking a 4.4-point improvement over ten years. The country treats 100% of its urban wastewater, achieving a high 89.1 in Water Resources, and protects a significant share of its land and seas, reflected in its 82.4 Biodiversity & Habitat score.

Germany’s robust environmental policies are complemented by massive investments in green infrastructure and renewable energy. The nation’s cities are recognized for clean air, efficient public transport, and progressive urban planning. Germany’s approach demonstrates that sustainability can go hand in hand with industrial progress, though ongoing industrial emissions remain a challenge.

4. Finland (EPI Score: 73.7)

Finland secures the fourth spot with a 2024 EPI score of 73.7, though this reflects a slight decrease from its 2014 score. The country is a global leader in public health, scoring a perfect 100.0 in both Sanitation & Drinking Water and Heavy Metals. Finland’s well-managed forests, protected natural areas, and clean air contribute to its strong ecosystem vitality.

The nation’s deep cultural connection to nature is evident in its policies, which seamlessly integrate sustainability into daily life. Finland’s challenge lies in maintaining its high standards amid growing urbanization and climate pressures.

5. United Kingdom (EPI Score: 72.7)

The United Kingdom earns an EPI score of 72.7 in 2024, up by 2.1 points over the past decade. The UK has made significant progress in reducing carbon emissions, largely through aggressive wind energy deployment and expanded recycling programs. Urban green spaces and biodiversity conservation have improved city livability and environmental health.

The UK continues to update its climate policies to meet international targets, but faces ongoing challenges with air quality in some metropolitan areas and the need for further emissions reductions.

6. Sweden (EPI Score: 70.5)

Sweden ranks sixth with a 2024 EPI score of 70.5, showing a modest 1.6-point increase over ten years. The country’s energy mix is dominated by hydropower and wind, and it is a pioneer in negative emissions technologies.

Sweden’s cities are models of sustainable urban development, and the nation’s commitment to clean air, water, and biodiversity is unwavering. However, Sweden faces pressure to further reduce emissions from transportation and industry to meet its ambitious climate goals.

7. Norway (EPI Score: 70.0)

Norway holds the seventh position with a 2024 EPI score of 70.0, up 3.6 points over the last decade. The country boasts nearly universal access to clean drinking water and sanitation, and its electricity is almost entirely supplied by hydropower.

Norway’s proactive climate policies and investments in electric mobility and carbon capture have resulted in some of the world’s lowest per capita emissions. The country’s challenge is balancing oil and gas exports with its climate commitments.

8. Austria (EPI Score: 69.0)

Austria scores 69.0 on the 2024 EPI, reflecting a slight decrease of 0.3 points over ten years. The country excels in maintaining clean cities and countryside through strict agricultural and chemical regulations. Austria’s public transport system and urban planning support eco-living, while strong environmental laws ensure high water quality and effective waste management.

Austria’s challenge is to address areas of stagnation and reinvigorate progress on climate adaptation and emissions reduction.

9. Switzerland (EPI Score: 68.0)

Switzerland earns a 2024 EPI score of 68.0, up 1.8 points over the last decade. The country is renowned for its pristine landscapes, robust waste management, and advanced water treatment systems.

Switzerland’s environmental protection laws and public engagement in sustainability initiatives help maintain high living standards and ecological health. However, Switzerland must continue to innovate in renewable energy and reduce its ecological footprint to stay ahead.

10. Denmark (EPI Score: 67.9)

Denmark rounds out the top ten with an EPI score of 67.9 in 2024, a 1.7-point increase over ten years. The nation is a global leader in wind energy and urban planning that prioritizes cycling and green spaces. Denmark’s comprehensive recycling policies and low pollution levels make it a model for clean living. 

The country’s ongoing challenge is to further cut emissions from agriculture and transportation while maintaining economic growth.

How Are These Rankings Determined?

Environmental Performance Index (EPI):

• Uses 58 indicators across 11 categories, including air quality, water and sanitation, biodiversity, habitat protection, and climate policy.
• Weights environmental health (40%) and ecosystem vitality (60%) to reflect both immediate human well-being and long-term sustainability.
• Draws data from the WHO, UN, and other global agencies, providing a scorecard for each country and highlighting leaders and laggards.

Climate Change Performance Index (CCPI):

• Assesses four main categories: GHG emissions (40%), renewable energy (20%), energy use (20%), and climate policy (20%).
• Uses 14 indicators, combining quantitative data (from IEA, FAO, UNFCCC) and qualitative expert assessments of national and international climate policy.
• Covers 63 countries and the EU, representing over 90% of global GHG emissions.

These indices are not just academic—they guide policy, inform investment, and help countries benchmark progress toward sustainability goals. High-ranking countries typically have strong regulatory frameworks, transparent governance, and engaged civil societies, making them attractive for sustainable business and investment.

Why Does This Matter?

• Policy Guidance: Countries use EPI and CCPI data to set targets, track trends, and refine environmental policies.
• Business and Investment: High scores signal a favorable environment for green investment and sustainable business operations.
• Public Health: Clean air, water, and effective waste management directly improve quality of life and reduce healthcare costs.
• Global Leadership: These nations serve as models for others striving to balance economic growth with environmental stewardship.

Summary point

As environmental challenges grow increasingly urgent worldwide, the achievements of these top 10 cleanest countries in 2025 offer both inspiration and a practical roadmap for sustainable development. Their success demonstrates that with visionary leadership, innovative technologies, and committed public participation, it is possible to safeguard natural resources, improve public health, and foster economic growth simultaneously.

By learning from their policies and practices, other nations can accelerate their own journeys toward a cleaner, greener, and more resilient future—ensuring a healthier planet for generations to come

In a strategic move to broaden its global footprint, Turkish Airlines has submitted a binding offer to acquire a minority stake in the Spanish carrier Air Europa. This potential partnership is part of Turkish Airlines’ ambitious plan to strengthen its presence across Latin America, leveraging Air Europa’s established networks.

According to a statement from Turkish Airlines, the investment aligns with its long-term growth strategy outlined in the airline’s 2033 vision. "Following comprehensive feasibility studies, the investment has been assessed as consistent with our objectives for sustainable value creation," the airline noted.

By joining forces with Air Europa, Turkish Airlines aims to tap into new revenue streams and enhance operational diversity within both passenger and cargo sectors. Air Europa’s robust presence in the Iberian Peninsula and Latin American markets offers Turkish Airlines a strategic gateway to these key regions.

Financial terms of the proposed stake remain undisclosed, leaving industry watchers eager to learn more about the deal’s implications for the competitive landscape in international aviation.

This initiative underscores Turkish Airlines’ commitment to expanding its global reach while deepening its regional engagement across emerging markets.

In a significant legal dispute, British Airways (BA), the UK-based airline, has sued the Massachusetts Port Authority (Massport), the operator of Boston Logan International Airport (BOS), seeking compensation exceeding $290,000. The lawsuit stems from a June 2022 incident in which a British Airways Airbus A380 superjumbo was severely damaged due to malfunctioning ground power equipment at the airport.

The affected aircraft, a nine-year-old Airbus A380 registered G-XLEL, had just completed a transatlantic flight from London Heathrow to Boston on June 8, 2022. Upon arrival, it was assigned a gate where it would normally be connected to the airport's power supply through the jetbridge. However, on this occasion, the jetbridge's power unit was out of service, requiring the use of a mobile Ground Power Unit (GPU) instead.

British Airways alleges that this replacement GPU malfunctioned, causing extensive electrical damage to multiple systems on the aircraft.

This unexpected damage forced British Airways to cancel the aircraft’s return flight to London immediately, stranding hundreds of passengers and crew in Boston. The airline faced complex logistics for repairs, as it lacked local maintenance contracts capable of handling A380 electrical system repairs in Boston. Critical aircraft components were removed and flown back to London for assessment and repair before the aircraft itself was ferried empty to London for further servicing. Consequently, the aircraft was grounded for several weeks.

The aircraft in question was recently returned to service in November 2021 after pandemic-related storage, only to be taken out of operation again due to this incident. British Airways filed the lawsuit exactly three years and one day after the incident, claiming at least $293,000 in damages and associated operational costs. Alongside Massport, the lawsuit also named the manufacturer of the faulty GPU.

While details remain confidential, an out-of-court settlement was reached shortly after the lawsuit was served, bringing the dispute to a close without a public trial.

British Airways currently operates a fleet of 12 Airbus A380 aircraft, with G-XLEL among the newer members, delivered in 2016. The airline is planning an extensive refurbishment program for its A380 fleet, expected to commence later this year. The upgrade will introduce new First Class suites, the latest Club World business class seats, and refreshed World Traveller cabins, reducing total seat capacity to favor a more premium travel experience. The first of these refurbished aircraft is projected to return to service by mid-2026.

This incident underscores the critical importance of reliable airport ground support equipment and highlights the operational challenges airlines face when unexpected technical issues arise far from their maintenance bases. The settlement also reflects the serious financial and logistical implications such equipment failures can have on international air carriers.

Set to take flight in late 2026, Koala Airlines is poised to shake up Australia’s domestic aviation landscape by carving a unique niche outside the duopoly of Qantas and Virgin Australia. Unlike previous entrants that sought to compete head-on, Koala Airlines is crafting a fundamentally different business model focused on sustainability and underserved regional markets.

Led by CEO Bill Astling, a veteran with 45 years’ aviation experience, Koala Airlines is purposefully maintaining a low public profile, a strategic move to avoid giving established rivals a long lead time. The airline has yet to finalize its fleet or official routes but is targeting regional segments from major hubs like Sydney and Melbourne, focusing on connectivity gaps left by bigger players rather than popular trunk routes.

Astling emphasizes Koala is not following the conventional full-service or low-cost carrier molds but aims for a long-term, disciplined approach that learns from the failures of predecessors like Bonza and Rex. Bonza, a budget carrier that collapsed in 2024 after less than two years, faltered due to rapid expansion and route challenges—a fate Koala is determined to avoid by focusing on sustainable growth rather than market share frenzy.

Koala Airlines also brings innovative plans including its “Koala Tech” platform integrating automation and AI to enhance operations and passenger experience. It promises novel policies like holding fare payments in trust to rebuild traveler confidence, signaling a commitment to customer trust and industry innovation.

While Koala Airlines’ investors remain undisclosed, the airline insists that backing comes from aviation-savvy sources and that the company’s cautious but steady build-up reflects lessons learned from recent industry volatility. Experts acknowledge the steep challenges in Australia’s saturated domestic market but note Koala’s differentiated strategy and sustainability focus could carve a viable path—if supported by strong financial foundations and measured execution.

With a heritage link through its 2019 acquisition of Desert Air Safaris, which operated charter and air tours across Australia and the Pacific for over 50 years, Koala Airlines begins its journey not as a start-from-scratch newcomer but as a carefully positioned player ready to reshape Australian aviation in a new, strategic way.

In sum, Koala Airlines aims to be more than just another low-cost entrant; it is positioning itself as an innovative, sustainable, and regionally focused carrier set to begin operations by late 2026, bringing fresh competition and potentially new standards to Australia’s skies.

Philippine Airlines (PAL), the nation’s flag carrier, has soared to new heights as it was named the second best airline in Southeast Asia according to the 2025 Flyers’ Choice Awards by AirlineRatings.com. This achievement adds to PAL’s growing list of accolades, underscoring its rising popularity among travelers in the region.

Ranked just behind Singapore Airlines — a global aviation leader — PAL secured the runner-up spot as the most preferred airline in Southeast Asia. Malaysia Airlines rounded out the top three, capturing third place. What makes PAL’s ranking especially meaningful is that it stems directly from passenger votes, reflecting genuine traveler satisfaction rather than expert panels alone.

PAL President Richard Nuttall expressed gratitude for the recognition, highlighting that the Flyers’ Choice Awards are unique in being based solely on traveler feedback. “This honor reflects the trust and satisfaction that all of us in PAL strive to earn from passengers by delivering friendly service, an unwavering focus on safety and reliability, and genuine care that comes from the heart,” Nuttall said.

Unlike other AirlineRatings.com awards judged by aviation experts on safety and operational performance, the Flyers’ Choice Awards provide a snapshot of which carriers resonate most strongly with passengers on a personal level.

This latest accolade follows PAL’s recent recognition by Campaign Asia, which placed the airline as the best travel brand in the Philippines and second best in Southeast Asia. PAL outperformed other major names such as Cebu Pacific, Klook, and Emirates—highlighting its strong brand presence in the competitive travel market.

Adding to its impressive track record, PAL has frequently ranked among the most punctual airlines in Asia and the Pacific. Citing data from aviation analyst Cirium, PAL earned the title of the most on-time airline in the region as recently as April, boasting an 86.07% punctuality rate.

PAL’s success is also being fueled by a fleet modernization drive. The airline is set to receive its first Airbus A350-1000 by year’s end, greatly enhancing its long-haul capabilities. In addition, October will see the arrival of the first of 18 retrofitted A321ceos, featuring upgraded cabin interiors and improved in-flight entertainment to elevate passenger comfort and experience.

With its sights set on innovation and excellence, Philippine Airlines continues to win the hearts of travelers, proving it is more than just a carrier — it’s a beloved symbol of Filipino pride in the skies.

Turkish Airlines is close to securing a significant investment in the financially troubled Spanish carrier Air Europa, positioning itself as the leading bidder amid recent withdrawals by other major aviation groups. According to reports by Spanish newspaper El Español and aviation news sources, Turkish Airlines is advancing rapidly in negotiations with Air Europa’s parent company, Globalia, with a deal possibly imminent. The stake discussed is believed to be around 25%, which would infuse approximately EUR 240 million (USD 275 million) of fresh capital into Air Europa.

Air Europa, owned 80% by Globalia and 20% by International Airlines Group (IAG), has attracted interest from various European giants, including Lufthansa and Air France-KLM. However, Air France-KLM has formally withdrawn from the bidding process, citing an inability to reach agreement with Globalia, although it continues its operational partnership with Air Europa as a fellow SkyTeam member.

Lufthansa CEO Carsten Spohr confirmed ongoing but challenging talks, describing the acquisition as “very difficult to get... to succeed.” Lufthansa has also ended its bid recently, leaving Turkish Airlines as the sole known contender.

The Turkish investment bid is strategic, enabling access to Madrid’s hub—Air Europa’s base—which offers valuable routes across Europe, Latin America, and transatlantic connections. This move aligns with Turkish Airlines’ ambition to bolster its European footprint and extend reach to Latin American destinations such as Miami, Buenos Aires, and São Paulo.

Analysts view the investment as a high-risk, high-reward opportunity given Air Europa’s precarious financials, including a looming repayment of EUR 475 million (USD 550 million) in pandemic-era government loans, alongside regulatory and operational uncertainties.

In parallel to seeking outside investment, Air Europa is negotiating a new loan worth about EUR 140 million (USD 160 million) with major Spanish banks to support its capital needs and manage its debt burden. The fresh capital from the potential Turkish Airlines stake combined with credit lines is seen as critical for stabilizing the airline’s finances.

While Turkish Airlines and Globalia have declined to comment publicly, these developments signal a potential significant shift in European aviation cross-border consolidation. If successful, Turkish Airlines would become a strategic partner in reorganizing Air Europa’s future, leveraging Madrid’s key geographic position to enhance connectivity across multiple continents.