With a nationwide lockdown in place, over 90 cities, including Delhi, recorded minimal air pollution in the last few days.

Welcoming the reduction in pollution, environmentalists urged the government to treat it as a 'wake-up call' and stop its 'obsession' with 'development' at the cost of the environment.

India is currently under the biggest lockdown with around 130 crore people asked to stay home in view of the coronavirus outbreak, which has claimed 19 lives and infected over 900 people in the country.

The government has urged people to avoid unnecessary travelling, significantly reducing the traffic movement across the country.

According to the Centre-run System of Air Quality and Weather Forecasting and Research (Safar), the impact of the measures taken due to the coronavirus outbreak has resulted in a drop in PM2.5 (fine particulate pollutant) by 30 per cent in Delhi and by 15 per cent in Ahmedabad and Pune.

The level of Nitrogen Oxide (NOx) pollution, which can increase the risk of respiratory conditions, has also reduced. NOx pollution is mainly caused due to a high motor vehicle traffic. In Pune, NOx pollution has reduced by 43 per cent, in Mumbai, by 38 per cent and in Ahmedabad, by 50 per cent.

Gufran Beig, a scientist at Safar, said generally in March, pollution is in the 'moderate' category (Air Quality Index range: 100-200) while presently, it is in the 'satisfactory' (AQI 50-100) or 'good' (AQI 0-50) category.

'It is the lockdown impact. Local factors like shutting down of industries and construction and traffic have contributed in improving the air quality. Rain is also helping, but the curbs on local emissions are playing a significant role,' he said.

Under the 'good' category, pollution is considered to be at the lowest and the air is believed to be the healthiest to breathe.

According to the data of the Central Pollution Control Board (CPCB), the air quality in the national capital is presently in the 'good' category. In Kanpur, which has high pollution levels, it is in the 'satisfactory' category. Moreover, 92 other cities with CPCB monitoring centres have recorded minimal air pollution, with the air quality in the range of 'good' to 'satisfactory'.

As many as 39 cities have recorded 'good' air quality and 51 cities have recorded 'satisfactory' air quality in the last few days, the CPCB data showed.

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.

Environmentalists believe that the reduced pollution levels should act as a wake-up call for the government.

Jyoti Pande Lavakare, co-founder, Care for Air NGO, said the low AQI and the blue skies proved beyond doubt that a lot of the polluted air was 'anthropomorphic, that is, man-made'.

'Obviously, slowing down the economy to such a degree is not the ideal way to bring down air pollution, but at least it proves that it can be done. We can achieve the same outcome by doing this mindfully, using technology and low-emission alternatives,' she said.

Lavakare emphasised on the need to realise that air pollution weakens the lungs, so countries like India with higher pollution and lower nutrition levels will be more affected by COVID-19, and morbidity and deaths are likely to be higher.

Ravina Kohli, environmentalist and part of the #MyRightToBreathe campaign, said it was a 'huge wake-up call' for governments obsessed with development at the cost of the environment.

'We the people are the problem. Our communication on solutions now also includes how to reduce pollution at a personal level by being able to understand our behaviour and its consequences on our environment.

'For the first time, I believe our present generation will discover the critical importance and need for a focus on public health and the quality of air we breathe,' she said.

Jai Dhar Gupta, environmentalist and founder of Nirvana Being that sells masks and purifiers to combat pollution, said humans need to figure out if they wish to go back to the normal that was there before or find a more sustainable normal.

'This has been a fantastic wake-up call and I think we had a reality check and we need to figure out a new normal. This is an opportunity, a chance to find a new sustainable life,' he said.