*SAFAR-LONG-TERM SCIENTIFIC PERSPECTIVE OF DELHI AIR (SINCE LOCKDOWN)* : *The long term nationwide lockdown has significantly reduced the emissions of various pollutants and the distribution of their concentration not only near the surface but all the way up vertically in the atmosphere. So there has been a huge reduction in accumulated emission mass. When the unlock period started, the fairly widespread to scattered monsoon rain under the influence of active monsoon trough and consecutive monsoon low-pressure systems originated in the Bay of Bengal and moved north westward continued to wash away particulate pollutants in Delhi and surrounding north Indian regions, not allowing any accumulation of pollution.* *There are indications that unlocking has not led to 100% of pre-COVID-19 levels due to many reduced activities.** Under such background, the high surface wind speed mainly from **South-easterly to easterly direction acted like a continuous "reset" button, **significantly helping to flush out whatever is getting accumulated even in present time. The easterly winds are also helping in blocking relatively dusty air from the dry arid western region. The unusual high wind speed during this time of the year for the past few days further cleaned the Delhi pollution and wind directions are such that it is just the opposite of what Delhi's **geographical and meteorological misfortune do during winter.*

*IN SUMMARY: The most fundamental parameter that is making Delhi air quality one of the best in recent years is the speed and direction of the wind in the past few days loaded with recent widespread rain and the lockdown related widespread cleansing. An ideal example of integrated natural experiment managing Delhi air in check from internal and external sources.*