Lockdown reduces pollution; AQI in Delhi turns 'good' from 'hazardous'

The sun shone bright in a cloudless blue sky in the national capital which recorded a significant drop in the mercury on Saturday due to intermittent rains over the last two days.

The city and its surrounding areas also recorded lowest concentrations of PM10, particulate matter 10 micrometers or less in diameter, since August 18 last year.

At 10 am, PM10 levels in Delhi-NCR stood at 32.5 microgram per cubic meter, the lowest since 15.9 g/m3 recorded on August 18 last year.

The national capital on Saturday witnessed cleanest air quality of the year so far with the overall AQI at 42, under the 'good' category.

According to the Centre-run System of Air Quality and Weather Forecasting (SAFAR), the air quality index (AQI) has improved due to the rains the city has been witnessing since Wednesday.

"The overall Delhi AQI is in the 'Good' category on Saturday morning. This is the cleanest air quality day of the year.

"Under the influence of western disturbance, rainfall observed over many places in the region. The regional air quality has improved significantly owing to the washout process," the SAFAR said.

The city's overall air quality index at 11 am stood at 40, which falls in the "good" category.

Environment and weather experts attributed the improvement in the air quality to the 21-day lockdown enforced to contain the spread of the coronavirus and rains and gusty winds due to successive western disturbances.

They said the air quality is expected to oscillate in the good or satisfactory categories due to the reduction in local sources of pollution -- vehicular pollution, construction dust, stack emissions etc -- due to the lockdown.

Delhi recorded a minimum of 15.7 degrees Celsius, four notches less than that recorded on Friday.

The Safdarjung Observatory, which provides representative figures for the national capital, recorded 5.3 mm rainfall till 8:30 am on Saturday.

The weather station at Palam recorded 3.2 mm rainfall.

The national capital has recorded 109.6 mm rainfall so far, the highest ever in March.

The weather office has predicted rains on Saturday as well. "The sky will remain generally cloudy with light rain or drizzle expected during the day," the India Meteorological Department said.

The minimum temperature on Saturday was recorded at 12.8 degrees Celsius, a notch below the normal, while the maximum will hover wound 25 degrees Celsius.

The city has witnessed 30.1 mm rainfall in the last 24 hours till 8.30 a.m.

Delhi witnessed one of the worst air quality days last year during winters.

The air in the national capital was so toxic after Diwali that the Environmental Pollution (Prevention and Control) Authority (EPCA) had declared a public health emergency in the Delhi-NCR and had advised people, especially children and the aged, to limit their exposure to the environment.