Delhi air pollution to spike in November, set to peak after Diwali
Air quality to worsen due to change in wind direction, warns Environment Pollution (Prevention and Control) Authority.Updated: Oct 26, 2018 07:50 IST
Air pollution in the national capital is likely to peak from November 1 as toxic fumes from the stubble-burning regions of Punjab and Haryana could gush in because of a change in wind direction, the Supreme Court-appointed body Environment Pollution (Prevention and Control) Authority (EPCA) warned on Thursday.
Delhi air has already been ‘very poor’ on the air quality index (AQI) over the past two days, and conditions are likely to deteriorate further, according to predictions by the Central Pollution Control Board’s (CPCB) forecasting system and Safar, which comes under the Union ministry of earth sciences.
Delhi also witnessed its coldest day of the season so far on Thursday, when the minimum temperature dropped to 15 degrees Celsius, two degrees below normal.
“Weather conditions are projected to become adverse from November 1, according to the India Meteorological Department (IMD). The prediction is that winds would be coming from the west – Punjab and Haryana. Also the ‘ventilation index’ (which determines how fast pollutants get dispersed) and wind speed will go down,” said EPCA member Sunita Narain.
EPCA held a meeting on Thursday to review how measures to control ‘very poor’ and ‘severe’ air pollution listed under the Graded Response Action Plan (Grap) are being implemented. Emergency measures under Grap were rolled out in the National Capital Region (NCR) from October 15.
“We need to be more careful from November 1 onwards. It is because the period between November 1 and November 15 would be the toughest period. Crop burning will be at its peak, we have Diwali celebrations (November 7), and winter is approaching,” Narain added.
In November 2016, pollution in NCR spiked after Diwali and the city was engulfed in its worst smog in 17 years.
In 2017, Delhi was again enveloped by a thick haze as the air quality remained ‘severe’ for a week. The AQI value touched 486 on November 9, 2017, prompting chief minister Arvind Kejriwal to describe Delhi as a ”gas chamber”, declare a public health emergency, and order that schools be shut.
The city’s AQI was 328 on Wednesday, and on Thursday it worsened marginally to 331 – the highest so far this season. On a scale of 0-500, an AQI value between 301 and 400 indicates ‘very poor’ air quality, and value beyond 401 indicates ‘severe’ pollution.
CPCB’s task force is expected to hold a meeting on Friday to take stock of the worsening situation and the expected spike from November 1 onwards.
Experts have blamed the prevailing pollution level on unfavourable meteorological conditions, including a dip in temperature, low wind-speeds, and a cloudy sky, which are combining to keep pollutants suspended in the air.
These adverse weather conditions are unlikely to improve over the next few days.
“Things are already bad. Add to this, the pollution expected to be triggered on Diwali night now that Supreme Court has relaxed the ban on bursting fireworks. Only favourable wind condition could have brought some respite. But if the weather remains bad, Delhi could be in for another spell of smog in the first week of November,” said D Saha, former head of CPCB’s air quality laboratory.
The Supreme Court on Tuesday set a two-hour window for the use of low-emission firecrackers on Diwali night, but unlike last year, did not impose any ban on the sale of firecrackers in NCR.