YouTube provides you with the best time to post in their analytics section.

Go to Youtube Studio >> Analytics >> Audience >> When your viewers are on Youtube

You will find a chart there. That will show you when your viewers are most active on youtube. But you have to post some videos to see this section in your analytics.
So what to do if you are starting out? Just do some research on when your competitors are posting or you could post at night 8-10 pm or 2-5 pm in the afternoon. This is the time when most of the viewers are active on youtube in India

Hope you found this quick tip helpful.