The smog and haze that set in Delhi on Monday will continue for the next three days, Pune-based scientists with the System of Air Quality Forecasting and Research (SAFAR) have said. Dr Gufran Beig, chief project scientist of SAFAR, said pollution levels would rise by 30-60 per cent.
For more than two weeks, the average difference between the maximum and minimum temperatures has been 15 degrees, which has kept pollution levels in the moderate zone. Scientists said pollution levels would increase in the coming days as this difference would reduce. The prevailing calm wind conditions would also aid in the pollution being stagnant.
On Tuesday, the maximum particulate matter (PM)10 and PM2.5 levels recorded were 360 µg/m3 and 200 µg/m3, respectively. (The permissible levels for PM10 — huge dust particles — is 100 µg/m3 and PM2.5 — a harmful pollutant that leads to respiratory disorders among humans — is 60 µg/ m3).
Data available under SAFAR air quality forecasting system show that the minimum temperature in Delhi has been around 8-10 degrees Celsius for around two weeks, while the maximum has remained around 24-26 degrees.
While the minimum temperature will remain at the same level, maximum temperature will gradually drop, which may worsen particulate pollution in poor the to very poor category, Dr Sunil Peshin, head, environmental monitoring research centre, Delhi, said.
However, a dip in the day and night temperatures will keep the boundary layer at a much lower level and will not allow it to go up even during day, Dr Gufran Beig said.
Fog delays 200 flights, 30 trains
Dense fog and near-zero visibility conditions over Delhi and NCR caused major disruption to air, rail and road traffic on Tuesday. Over 200 flights were delayed, many by over five hours, while over 30 trains, including Rajdhani and Duronto, were running late by more than seven to eight hours.
At the Indira Gandhi International Airport, flight operations were completely closed on both runways from 4 am to 10 am on Tuesday. Airport officials said schedules of all flights went haywire after 5 am, when visibility dropped below 50 metres.
“The fog started to become dense around 5 am and the visibility went below 50 metres, the minimum required for landing under poor visibility conditions using the CAT-III B instrument landing system (ILS),” the official said.
Low visibility procedures (LVP) had to be initiated at 9.25 pm on Monday on Runway 29-11, and