October 15, 2025

Context: In a landmark conservation success, the International Union for Conservation of Nature (IUCN) has upgraded the Green Sea Turtle (Chelonia mydas) from Endangered to Least Concern. This reflects decades of global conservation efforts and improved protection of nesting beaches, feeding grounds, and migratory routes.

Population Recovery

Global populations of Green Sea Turtles have risen by approximately 28% since the 1970s, particularly in the Atlantic and Indo-Pacific regions. This rebound highlights the effectiveness of marine protected areas (MPAs), nesting site protection, and international conventions such as CITES and the Convention on Migratory Species (CMS).

However, certain regional subpopulations remain vulnerable due to localized habitat loss, fisheries bycatch, and illegal harvesting.

About the Green Sea Turtle (Chelonia mydas)

• Taxonomy: Belongs to the family Cheloniidae.
• Physical Traits: The largest hard-shelled sea turtle, named for the green hue of its body fat and cartilage, not its outer shell.
• Diet:
  • Hatchlings: Omnivorous, feeding on small invertebrates.
  • Adults: Strictly herbivorous, grazing on seagrasses and algae with beak-like jaws.
• Distribution: Found across tropical and subtropical oceans — the Atlantic, Pacific, and Indian Oceans, and parts of the Mediterranean.
  • In India: Occurs along the mainland coasts, Lakshadweep, and Andaman–Nicobar Islands, with key nesting sites in Saurashtra and Great Nicobar.
• Habitat:
  • Juveniles: Pelagic (open-ocean).
  • Adults: Shallow coastal waters, lagoons, coral reefs, and seagrass meadows.
• Migration: Extremely migratory, travelling thousands of kilometres between feeding and nesting sites, guided by Earth’s magnetic field.
• Reproduction: Temperature-dependent sex determination — warmer sand produces more females, cooler produces more males.

Ecological Importance

• Keystone Role: Grazing maintains healthy seagrass ecosystems, enhances carbon sequestration, and supports marine biodiversity.
• Indicator Species: As long-lived (~80 years) marine reptiles, their health reflects oceanic ecosystem stability.

Threats

Despite recovery, the species faces persistent threats:

• Overharvesting and illegal egg collection.
• Bycatch in trawl and gill nets.
• Coastal development and light pollution disrupting nesting.
• Climate change altering sex ratios and nesting patterns.

Conservation Framework

Conclusion

The upgradation of the Green Sea Turtle signals a major global conservation win and reinforces the impact of sustained community engagement, habitat protection, and international cooperation.

Continued vigilance is essential to ensure that regional populations also recover fully and the species continues to thrive as a vital guardian of marine ecosystems.

Context: The National Green Tribunal (NGT) has taken suo motu cognisance of a report highlighting the alarming rise of ground-level ozone pollution across major Indian cities. The tribunal noted that elevated ozone levels are closely linked to vehicular, industrial, and power-sector emissions of nitrogen oxides (NOx) and directed the Central Pollution Control Board (CPCB) to conduct an expert study and frame control measures.

Understanding Ozone Pollution

Ozone (O₃) is a gas formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. It is a secondary pollutant, meaning it is not directly emitted but produced through chemical reactions in the atmosphere.

• Stratospheric ozone (“good” ozone): Forms the ozone layer that protects Earth from harmful ultraviolet (UV) radiation.
• Tropospheric ozone (“bad” ozone): Accumulates near the ground, acting as a major air pollutant harmful to human health, vegetation, and ecosystems.

Scale of the Problem

• Ozone Exceedance: Highest levels recorded in Delhi-NCR and Mumbai, frequently breaching CPCB safe limits (2025).
• Rising Trend: Urban ground-level ozone has increased by over 30% since 2018, driven by vehicular exhaust, power generation, and industrial activity (MoEFCC, 2024).
• Health Impact: Linked to ~70,000 premature deaths annually in India (WHO, 2024) due to respiratory and cardiovascular diseases.
• Emission Sources:
  • Transport sector: ~40% of NOx emissions.
  • Power generation: ~30% of NOx emissions.
• Environmental Impact: Reduces crop yields by 5–20%, damages forests, and contributes to climate warming by trapping heat.

Regulatory and Policy Response

• NGT Directive (2025): Seeks a CPCB-led expert study on ozone sources and regional control strategies.
• National Clean Air Programme (NCAP): Focuses on reducing particulate matter (PM₂.₅ and PM₁₀), but experts now call for integrating ozone metrics into air quality management.
• CPCB Initiatives: Expanding ozone monitoring networks and promoting real-time data sharing.
• Urban Interventions: Transition to cleaner fuels, e-mobility, renewable power, and stricter NOx emission norms for industries.

Way Forward

• Develop Ozone Action Plans under NCAP focusing on precursor emission control.
• Promote electric mobility, public transport, and low-NOx technologies in thermal plants.
• Enhance green cover and urban ventilation corridors to disperse pollutants.
• Strengthen public awareness on ozone exposure risks and adaptive health measures.