Official business hours are 9.30am to 5.30pm Monday to Friday. Unofficially they tend to be 10am to 5pm.
Most major banks are open from 10am to 2pm (some from 9am to 1pm and 1.30pm to 3pm ) on weekdays, and 10am to noon on Saturday – there are often variations, so it pays to check. Travellers-cheque transactions usually cease 30 minutes before the official bank closing time. In big cities and some tourist centres there are some foreign exchange offices that stay open longer.
In the state capitals, the main post office is generally open from 10am to 5pm on weekdays and on Saturday morning.
Shop hours vary regionally, but most tend to open from around 10am to late afternoon (around 6pm ) daily except Sunday. However you definitely should check locally so you don’t leave all your shopping to the last day of your trip only to find that’s the day shops are closed!