WHICH IS CORRECT -HE AGAIN VISITED INDIA ON AUGUST 1980
OR HE AGAIN VISITED INDIA IN AUGUST 1980
"in"
"on" means on a particular day, but you use "in" when you don't state a particular day.
OR HE AGAIN VISITED INDIA IN AUGUST 1980
"on" means on a particular day, but you use "in" when you don't state a particular day.