Severe air pollution: IITM study pins the blame on Delhi's neighbours

Cities like Jhajjar, Rohtak, Sonipat and Panipat were the biggest contributors to emissions from outside Delhi at 5 per cent, says the study

As the air quality in Delhi deteriorates to severe levels, a debate has begun on how much of this pollution is caused by local factors. A new report says that sources outside the city mainly cause air pollution in the national capital.

The decision support system (DSS) of the Pune-based Indian Institute of Tropical Meteorology, an autonomous body, said local pollution sources contributed between 20-30 per cent of the total PM2.5 volume; the rest came from sources outside Delhi, according to a report in The Times Of India.

Citing DSS, the report said NCR towns and others account for 40-45 per cent of Delhi's pollution if the city's pollution sources like transport, construction (essential projects or violations), industries, and biomass burning (in Punjab and elsewhere) are taken out of the equation.

Cities like Jhajjar, Rohtak, Sonipat and Panipat were the biggest contributors to emissions from outside Delhi at 5 per cent. It said that stubble smoke accounted for 28 per cent of the capital's pollution.

Among local sources, the transport sector contributed the most (14 per cent) to Delhi's air quality woes.

Elevated PM2.5 levels in the air reduce visibility and cause the air to appear hazy. These tiny particles may also cause serious health issues following long exposure.

The IITM report came when the authorities announced that they are implementing the strictest anti-pollution measures under Graded Response Action Plan (GRAP) with immediate effect. This action included a ban on plying of diesel-operated four-wheelers in Delhi, except for those carrying essential commodities or providing essential services.

According to the weather forecast, the overall air quality over Delhi will likely remain in the 'severe' or 'severe +' category between November 3 and 5. On Friday morning, Delhi's Air Quality Index (AQI) had jumped to 472. An AQI from 400 to 500 or above is considered 'severe'.

The weather office forecast says the air quality in Delhi is expected to improve gradually after November 5.