Delhi weather today may bring some relief to residents facing severe air pollution, with the weather department forecasting light drizzle in parts of the national capital. Any improvement in air quality, however, is expected to depend on the amount of rain and wind speed, according to the report.
The forecast is linked to the influence of a western disturbance over the higher Himalayan regions. Its impact is expected to extend to several northern plains, including Punjab, Haryana, parts of Rajasthan, Delhi and western Uttar Pradesh, where light rain or drizzle may occur.
Delhi’s average air quality index stood at 367 on Saturday, according to Central Pollution Control Board data. This falls in the ‘very poor’ category and was only marginally lower than the previous day’s average of 373. The AQI had been recorded at 348 at 8 am on Saturday, but the pollution level rose again after wind speeds weakened.
The report said 17 areas of Delhi recorded an AQI above 400 on Saturday, placing them in the ‘severe’ category. The conditions have followed a sharp deterioration in air quality since the beginning of November. Air quality had remained comparatively better until October, but pollution levels began rising rapidly in the first part of the month.
Temperatures have also remained above normal for this period. The Safdarjung weather station recorded a maximum temperature of 30.4 degrees Celsius on Saturday, which was 1.9 degrees Celsius above normal.
The possible effect of drizzle on pollution will depend on how much rain falls and whether wind speeds improve. Rain can temporarily reduce airborne particles, but the report does not establish how long any improvement would last. The immediate air-quality situation therefore remains dependent on weather conditions and atmospheric movement.
The report also cited an analysis by Climate Trends of CPCB data released around Diwali. It found that Delhi’s average PM2.5 concentration on November 8 was 290 micrograms per cubic metre, compared with India’s 24-hour standard of 60 micrograms per cubic metre. The level was therefore nearly five times the national standard.
Climate Trends said the increase in PM2.5 after Diwali was 57 points this year, compared with a 146-point increase last year. The year-on-year difference was partly attributed to Delhi’s already high pollution levels before Diwali. The report said PM2.5 rose 25% after Diwali this year, compared with a 134% increase during the corresponding period last year.
The forecast drizzle is expected to be the next weather-related factor affecting Delhi’s air quality. Residents and agencies will need to track the rainfall, wind movement and subsequent CPCB readings to determine whether the improvement is substantial and sustained.
