Delhi’s Air Quality Enters ‘Red Zone’ Ahead of Diwali, Pollution Mainly Due to ‘Local Sources’

The PM2.5 concentration in the national capital can surpass 300 micrograms per cubic metre on November 5. The safe limit is 60 micrograms per cubic metre.

New Delhi: The air quality in the national capital on Tuesday entered the “very poor” category for the first time ahead of Diwali. The poor air quality is due to unfavourable conditions for dispersion of pollutants, authorities said. As per updates, the stubble burning accounted for six per cent of PM2.5 pollution in Delhi and the rest of the pollution is due to local sources, Gufran Beig, the founder project director of SAFAR, a government framework for air quality forecasts, said.

However, the Indian Meteorological Department’s (IMD) predicted that the air quality in Delhi may dip to the “very poor” category a day after Diwali.

It must be noted that the AQI is a number used by government agencies to assess and communicate air pollution levels to the public. A higher AQI indicates unfavourable health effects for a huge proportion of the population. An AQI between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

As per updates from Central Pollution Control Board, Delhi recorded a 24-hour average air quality index (AQI) of 303. However, the air quality index was 281 on Monday, 289 on Sunday and 268 on Saturday. Faridabad recorded air quality index at 306, Ghaziabad (334), and Noida (303).

Under the zero firecracker emission scenario, Delhi’s PM2.5 concentration is predicted to be in the upper end of the ‘very poor’ category from November 4 to November 6.

“However, even if we consider 50 per cent of firecracker-related emissions of 2019, the AQI is predicted to degrade to the ‘severe’ category from November 4 night and will remain so till November 5,” SAFAR said.

The PM2.5 concentration in the national capital can surpass 300 micrograms per cubic metre on November 5. The safe limit is 60 micrograms per cubic metre.

The contribution of farm fires in Delhi’s air pollution has remained low this season so far due to the record-breaking rainfall in October and “unfavourable” wind direction.

However, it is likely to go up to 40 per cent by November 5 as the wind direction is expected to change northwesterly after Diwali, said Gufran Beig, the founder project director of SAFAR.

Northwesterly winds carry smoke from farm fires in Punjab and Haryana towards the national capital.

Last year, the share of stubble burning in Delhi’s pollution had peaked at 42 per cent on November 5. In 2019, crop residue burning accounted for 44 per cent of Delhi’s PM2.5 pollution on November 1.

The air quality in the national capital entered the very ‘poor’ category for the first time this season on Tuesday owing to unfavourable conditions for dispersion of pollutants, authorities said.