Xiaomi Smart Air Purifier 4 Lite

Purifier changed PM2.5 Level from 460 to 70 in less than 30 minutes apparently( according to its on meter)

I ordered, and it was delivered the next day, but I am still following up on the warranty card, which should have been delivered with the product though i called sales centre but situation is still not encouraging and it's grey . Anyways product is delivered it's been a week now since I am using this for room like 10x 10 it's good but if you are planning to go with bigger room you should go for some bigger some. Need all doors closed else the reading will jumped up within no time .it's not a product fault but the atmosphere where are in.