People forced indoors, AQI improves in polluted cities
IN INDIA, SEVERAL CITIES KNOWN FOR HIGH POLLUTION LEVELS HAVE RECORDED AN IMPROVEMENT IN AIR QUALITY SINCE FRIDAY
NEW DELHI : There has been a general improvement in the air quality, including in India, amid lockdowns imposed across the world to check the spread of the coronavirus pandemic (Covid-19) with the European Space Agency (ESA) releasing satellite images showing nitrogen dioxide (NO2) levels have plummeted drastically.
The levels of nitrogen dioxide, a pollutant emitted generally by motor vehicles, went down drastically during the lockdown period in parts of China, from where the pandemic originated, and then gradually rose again in the past few days when the restrictions were eased.
In India, several cities known for high pollution levels have recorded an improvement in air quality since Friday. A voluntary curfew to check the spread of the disease kept people mostly indoors on Sunday and the lockdown has been extended till the end of March in places like Delhi.
Gurugram’s air quality index (AQI) improved to 91 to reach the satisfactory category on Monday. AQI of Lucknow improved to 135 to moderate on Monday. Kolkata, which had an AQI of 123 in the moderate level, fell to 108. Mumbai’s AQI was 64 bordering good air quality on Monday.
Delhi invoked the Delhi Epidemic Disease Covid-19 Regulations, on March 12 which gives the government powers to take extraordinary steps to combat an outbreak. Before the lockdown, Delhi had shut schools, restricted gatherings of more than five people and closed cinemas. The average AQI between March 13 and 22 in Delhi has been 161.4 compared to 190.5 last year.
“The lockdown is catalysing systemic changes, which can be sustained beyond the corona crinature’s sis. We are setting up a system to work with less travel. We are now trying to realise the full potential of digitisation. We had not explored this alternative earlier. Reduction in emissions will also happen because of shutting down of factories and industries. That will show us the benefit of switching to clean fuel,” said Anumita Roychowdhury, executive director, Centre for Science and Environment.
Neha Sinha, a Delhi-based conservation biologist, said: “The time of isolation could be seen as an opportunity to understand processes and identify what we share our city with. This is a good time to do solitary backyard birding: there are lots of birds that have migrated to India and are still here.”
For China, ESA used data from the Copernicus Sentinel-5P satellite, which shows the NO2 emissions from December 20 to March 16. “The drop in emissions in late January is visible, coinciding with the nationwide quarantine, and from the beginning of March, the nitrogen dioxide levels have begun to increase,” the analysis released on Thursday said.
The Copernicus Atmosphere Monitoring Service also recorded a decrease of fine particulate matter (PM) concentrations in China in February compared to the previous three years. Studies based on satellite observations and detailed computer models of the atmosphere indicated a reduction of around 20-30% in PM concentrations over large parts of
China, it said. “We can attribute a part of the nitrogen dioxide emission reduction to the impact of the coronavirus. We see around a 40% reduction over Chinese cities. However, these are just rough estimates, as weather also has an impact on emissions,” said Claus Zehner, ESA’s Copernicus Sentinel-5P mission manager.
With boat traffic reducing in Venice following orders of stopping all non-essential travel in several cities in Italy, residents posted pictures showing clean water in Venice’s canals.
Some from California tweeted that Los Angeles seemed to have the freshest air ever with the lockdown. Modacity, an organisation that promotes cycling in the Netherlands, tweeted: “The 1973 oil crisis opened Dutch people’s eyes to the amount of space reserved for cars. Might the current situation be having a similar effect on places such as Bogota, New York and Melbourne?”