Air quality in Delhi dipped slightly

The air quality in Delhi-NCR dipped slightly on Monday but is expected to improve in the next 24 hours as widespread rains are likely.

Weather experts said a dip in the wind speed -- from 10-12 kilometers per hour to 5-6 kmph -- led to the deterioration of air quality in the region.

The overall air quality index (AQI) in the city read 252 at 4 pm on Monday, up from 234 at 4 pm on Sunday.

Most of the 37 air quality monitoring stations in Delhi recorded AQI in the "poor" category.

Neighbouring Ghaziabad (255), Greater Noida (234), Gurgaon (232), Faridabad (221) and Noida (236) also witnessed an increase in pollution levels.

Light rains are expected in northwest India on Tuesday and Wednesday.

If Punjab and Haryana receive widespread rains, the impact of stubble burning on Delhi's air quality will reduce further, a weather expert said.

However, light rains in Delhi-NCR may prove counterproductive as they increase humidity which exacerbate pollution, he said.

In case of good rains in Delhi-NCR on November 26 and 27, pollutants will be washed away.

The government's air quality monitoring and forecasting body SAFAR also said there is a possibility of showers on Tuesday which may improve air quality (if sufficient rain occur).

"The farm fire count is 463, which is sufficiently high, and wind arriving to Delhi are from north but the contribution of stubble plume in Delhi's air quality is marginal," it said.

This is due to high-velocity upper air transport-level winds which would carry the plume without descending in Delhi, the SAFAR said.

"It shows that fire counts are not directly proportional to deterioration of Delhi's AQI and meteorology plays a decisive role," it said.

Skymet weather, a private weather forecasting agency too said, that Delhi NCR is likely to see a rainy spell between November 25 and November 28.

Delhi could receive moderate rains on Tuesday and Wednesday and the temperatures are expected to dip to "single-digit minimum".

"After the rains, we expect the air quality to improve," it said in a statement.