Novel coronavirus reduces air pollution in China

The National Aeronautical and Space Administration (NASA) has found that
Novel coronavirus (COVID-19) led to a sharp decline in pollution levels...
across China
A decline in nitrogen dioxide (NO2) levels was first noticed near Wuhan,
epicentre of the outbreak
and eventually spread across the whole of China
NASA maps compared emissions...
from January 1-20, 2020 — before quarantine was imposed,
and February 10-25, 2020, after the safeguards were in place
NO2 is highly noxious
and can lead to severe respiratory problems
A report from climate change tracking website Carbon Watch