The prepositions at, in and on are associated with specific time categories, Usages are as follows.
1. at : clock times, exact times of day, night, holiday periods
example - at 3:45 PM / at noon/ at sunrise

2. in : months, years, morning/afternoon/evening, seasons, centuries, eras
example - in June / in the morning / in the '70s / in the winter

3. on : days, dates, holidays, weekends, days+morning/afternoon/evening
example - on Tuesday / on the weekend /on Friday mornings

Ashwin become India's second-highest wicket-taker in Tests