Even as Delhiites woke up to mild showers in different parts of the city early on Sunday, the air quality worsened resulting in a thicker blanket of smog and low visibility. This hampered flight operations at the Delhi airport on Sunday afternoon. However, all category-2 compliant pilots were able to operate, Delhi airport authorities said in a statement. At least five Vistara flights, 12 Air India flights were diverted and several were delayed due to poor visibility in Delhi.

#FlyAI : Due to poor visibility conditions at @DelhiAirport arrival and departure of flights are delayed. ETD for few flights have been revised. Pax are advised to check flt status before leaving for Apt. To get timely updates pl ensure your contact details are updated with us. Air India (@airindiain) November 3, 2019

While the cloudy sky and haze prevented the Chhath devotees from getting a glimpse of the rising sun on the final day of the four-day festival, the mild spell also failed to provide any respite from the 'severe' level of pollution in parts of the National Capital Region (NCR).

Air quality deteriorated further but remained in the 'severe' category in Delhi-NCR on Sunday, with the pollution level hovering at 447. The air quality in Delhi and the surrounding regions has remained in the 'severe' category despite the wind activity which had picked up on Saturday evening.

On Sunday, all the pollution measuring stations in Delhi-NCR showed a severe pollution level but on a very higher side.

Two days after the Delhi-NCR recorded its worst air quality forcing authorities to shut schools, ban construction activities and declare a public health emergency, the overall Air Quality Index (AQI) was at 447 at 5:30 am. The overall AQI in Delhi was 402 at 8 pm on Saturday.

Even after dampening rain, Delhi’s air pollution is so thick you can’t see the city. Air quality index (AQI) is at a putrid 723+. The international threshold for health-threatening pollution is 30. pic.twitter.com/a5QpNfXQPw Siobhan Heanue (@siobhanheanue) November 3, 2019

The air quality in Anand Vihar was recorded at 478 and 463 at Alipur. The most deteriorated air quality, 486, was recorded at ITO. Most areas recorded an AQI of above 450 on Sunday morning.

An AQI between 0-50 is considered 'good', 51-100 'satisfactory', 101-200 'moderate', 201-300 'poor', 301-400 'very poor' and 401-500 'severe'. The air quality above 500 falls in the 'severe plus' category.

Rain increases pollution, leaves scientists stumped

Even early mornings showers and windy conditions have failed to bring down pollution levels in the capital. In fact, the change in weather has adversely affected air quality -- puzzling environmental experts.

Experts are in a fix over how to explain the development. Some experts believe that the Sunday morning rain has been too little to affect pollutants in the air. Instead of bringing relief, the rain has caused pollutant particles to become more concentrated due to humidity.

This is because of the direction of the wind which is coming from Haryana and Punjab towards Delhi and might be carrying remnants of stubble burning with it.

The situation is such, that pollution in Delhi has increased as compared to yesterday and visibility has reduced greatly. Climate experts believe the situation is likely to improve on Monday.

The share of stubble burning in Delhi's pollution reduced from 44 per cent on Friday, the season's highest, to 17 per cent on Saturday, government air quality monitor SAFAR said.

A Supreme Court mandated panel on Friday declared a public health emergency in Delhi-NCR in view of alarming levels of air pollution and imposed a ban on all construction activities till November 5.

Earlier, the Environment Pollution (Prevention and Control) Authority had banned construction activities only for the period between 6 pm and 10 am till November 2. Now, no construction can take place even in day time.

Delhi receives mild showers, visuals from INA flyover. pic.twitter.com/6fvSTFu4SG ANI (@ANI) November 3, 2019

Meanwhile, the authorities on Saturday arrested 38 people including a director and three engineers, from sites of five real estate groups in Noida and Greater Noida for carrying out construction activities despite the ban.

While Skymet had predicted that parts of Delhi-NCR would receive light showers on Saturday evening, experts said air pollution would remain as bad as it has been for the past few days and people would have to wait for five more days for a good amount of rain.

While the drizzles cannot dilute the pollutants, it has been expected that the NCR could witness a good amount of rain along with good wind speed facilitating respite from bad air on November 7 and 8.