Delhi air quality worsens ahead of Diwali as firework restrictions enter force

Delhi is once again battling worsening air pollution as the onset of winter brings a familiar deterioration in air quality to India's capital. The city's air quality index (AQI) - which measures PM2.5, fine particulate matter that can clog lungs - has crossed 300, entering the "very poor" category and raising health concerns for millions of residents.

Breathing such polluted air over prolonged periods can cause respiratory problems and worsen existing illnesses, with children and older people particularly vulnerable. Authorities have responded by invoking Stage II of the Graded Response Action Plan (GRAP), introducing measures to curb dust, vehicle emissions and other sources of pollution.

GRAP is a set of emergency measures that become progressively stricter as pollution levels rise. The latest restrictions include more intensive road cleaning, higher parking charges to discourage private vehicle use and increased public transport services.