can someone suggest me best price tracking site for big sale on amazon and flipakrt and chroma

You'll only find it for Amazon since it's international, i.e. Keepa.com

Those for Indian sites are there but data isn't as reliable.

use simple google search for price websites and compare using multiple price website for the same product and you will find the weighted average of past price using it

1. Keepa.com
2. Pricehistory
3. Desidime (You can search the item and check if any deals posted in the past by the dimers, check price of that deals, you'll get an idea that current price is high or low..)