Each year on September 16, the world comes together to celebrate World Ozone Day, a reminder of the ozone layer’s importance and the shared responsibility of safeguarding it. This thin band of gas in the stratosphere acts as Earth’s sunscreen, filtering out ultraviolet rays that can damage human health, ecosystems, and food systems. Without it, life as we know it would be at grave risk. The 2025 theme, “From Science to Global Action,” underlines the journey of ozone protection — from early scientific warnings about its depletion to unprecedented international cooperation through the Montreal Protocol of 1987. This year is especially significant as it commemorates the 40th anniversary of the Vienna Convention (1985), the treaty that created the foundation for these landmark agreements. Together, they remain models of how science-led diplomacy can resolve a global environmental crisis. Encouragingly, the ozone layer is on a path to recovery. But the struggle is far from over. For India, World Ozone Day represents both a celebration and a challenge. Since joining the Montreal Protocol in 1992, India has phased out harmful substances like CFCs, Halons, and carbon tetrachloride. Its progress in eliminating HCFCs — expected to be fully phased out by the end of 2024 — illustrates the country’s seriousness.
Central to this success has been the Ozone Cell of the Ministry of Environment, which coordinates policy, industry action, and international collaboration. However, while stratospheric ozone heals, surface ozone pollution is emerging as a pressing danger. Unlike the protective upper layer, ground-level ozone is a pollutant created by chemical reactions involving nitrogen oxides and volatile compounds, often worsened by extreme heat. India’s increasing heatwaves magnify this problem, making it a public health crisis. The threat also extends to food security. Ozone damages crops such as wheat and rice, reducing both yield and quality. In a country where agriculture sustains millions, this poses grave economic and social risks.
With 13 of the world’s 20 most polluted cities located in India, the crisis is compounded by dense populations, industrial growth, and an ageing demographic more vulnerable to respiratory illness. Addressing surface ozone is complex, since ozone is not emitted directly but formed in the atmosphere. Effective action requires cutting precursor gases, strengthening monitoring systems, and adopting innovative urban policies. Cities could reduce exposure by restricting fuel refilling during peak sunlight hours or shifting energy-intensive industrial activities to cooler times of the day. Expanding clean energy, electric vehicles, and stricter emission standards are critical to tackling the root causes. The India Cooling Action Plan (ICAP) promotes sustainable, energy-efficient cooling, cutting reliance on harmful HFCs. Transitioning to renewables, investing in public transport, and cleaner urban planning are shaping the way forward. World Ozone Day 2025 offers two powerful lessons. First, international cooperation works — the near-recovery of the ozone layer is proof of what science-guided policy can achieve. Second, new challenges demand new solutions — surface ozone pollution must be tackled urgently, especially in vulnerable nations like India.
Protecting the stratospheric ozone and reducing surface ozone are vital not only for the planet’s health but also for humanity’s survival. By embracing innovation, collaboration, and accountability, India can stand as a global example of resilience and leadership.
The writer is a Doctoral Fellow and Visiting Faculty, FDDI, Ministry of Commerce and Industry, Government of India