India, Dec. 24 -- A large share of India's PM2.5 pollution is not emitted directly but is chemically formed in the atmosphere from precursor gases, according to a new analysis by the Centre for Research on Energy and Clean Air (CREA).

Up to 42 per cent of India's PM2.5 burden is secondary particulate matter, primarily ammonium sulphate formed from sulphur dioxide (SO2), the assessment has found.

India is the largest SO2 emitter globally, with coal-fired power plants contributing at least 60 per cent of national SO2 emissions, reinforcing the central role of SO2 control in reducing PM2.5 pollution.

Despite this evidence, the current regulatory framework has exempted around 78 per cent of coal-fired power plants from installing flue gas ...