Most of the participants on CodeChef are from India.
8-10 PM IST is dinner time in India.
(Also 8-10 PM dinner time everywhere in their local time).
See other platforms, to maximize participants from their country, they have very good contest timings, most of the doesn’t conflict with dinner timings.
Platform | Country | Timing (Local Time)
LeetCode | China | 10:30 pm / 10:30 am
AtCoder | Japan | 9 pm
Codeforces| Russia | 5:30 pm
Coding Ninjas | India | 9 PM onwards, or 6 PM onwards
It’s better to start CodeChef contests after 9 PM IST, or prepone it to 7 PM IST.