Rain gives Delhi a breather – but experts warn of the smog winter ahead

What happened

On Monday morning Delhi's average air quality index (AQI) stood at 164, according to the Central Pollution Control Board (CPCB). As recently as Friday it had been 230, in the 'poor' range. The improvement came with a weak weather system: light rain fell overnight into Sunday, with hail in places; the Safdarjung station recorded 4.4 millimetres.

The average hides big differences. Several monitoring stations still reported values above 200, including Jahangirpuri at 246, Vivek Vihar at 235 and R.K. Puram at 223. The main pollutant is PM2.5, fine particulate matter that penetrates deep into the lungs.

Since 21 October, stage one of the GRAP emergency plan has applied across the capital region. Restaurants and eateries may not use coal or firewood in tandoor ovens, and diesel generators are restricted to emergencies. More light rain is forecast for 29 and 30 October.

The mood on the ground

Pictures from Sunday showed commuters on rain-soaked roads and traffic police in raincoats. For many the rain was a welcome interruption – but local media are sceptical that the cleaner air will last.

Environmental experts interviewed by ETV Bharat describe the improvement as only temporary. Rain and wind disperse pollutants briefly, they say, but the sources – vehicle exhaust, road dust, construction and waste burning – remain. One expert thinks the air could stay moderate until Diwali, but warns of the extra load from fireworks.

Others argue that Delhi relies too heavily on favourable weather instead of cutting emissions year-round. One specialist expects repeated very poor to severe readings in December and January. Doctors quoted by Patrika advise against jogging or long walks outdoors on bad days and recommend well-fitting N95 masks, especially for children, older people and those with heart conditions.

Voices from the media