The price depends on different factors, and the season is one of them. While the climate in India depends on the region, if you are about to arrive in Delhi, you should consider its weather. It has a monsoon season that begins in July and lasts until September, which is the low season.
Going to the country some time between October and December will allow you to enjoy reasonable ticket prices; however, you should be ready for rains. Winter is the peak season, during which prices go up.