
Philips
Philips AC0920 Smart Air Purifier
Bedrooms up to about 300 sq ft
Its 250 m³/h CADR and HEPA NanoProtect filter suit a room of about 300 sq ft, per Philips India.
Look for a True HEPA filter and go by CADR, since brands work out the room size on the box in different ways. In a Delhi winter it may run on high all day, so check the noise and filter prices.
The cheapest one worth buying.

Philips
Bedrooms up to about 300 sq ft
Its 250 m³/h CADR and HEPA NanoProtect filter suit a room of about 300 sq ft, per Philips India.
Where most people should land.

Coway
Living rooms up to 355 sq ft
Its True HEPA and carbon filter is rated for 8,500 hours, nearly a year of 24/7 use, per the listing.
The best one worth paying for.

Coway
Living rooms and open-plan spaces up to about 930 sq ft
Rated at a CADR of 249 cfm for smoke (about 420 m³/h), enough for 930 sq ft at two air changes an hour.
Not sure which level fits you? Tell the AI how you'll use it.
Ask which level fits me