What contributed to a decline in Delhi's pollution levels

Observations

During lockdown (from March 25 to June 1) the PM 10 and PM 2.5 levels reduced by 35% to 40%

Reduction in pollution level from industries- 10%

Reduction in transport movement- 15%

Reduction in dust levels10-15% (Because of reduced traffic movement, dust re-circulation was lower)

Some reduction from other activities such as refuse burning, airport, etc. as well