The Negotiable Instruments Act, 1881
§106 — Reasonable time of giving notice of dishonour
If the holder and the party to whom notice of dishonour is given carry on business or live (as the case may be) in different places, such notice is given within a reasonable time if it is dispatched by the next post or on the day next after the day of dishonour. If the said parties carry on business or live in the same place, such notice is given within a reasonable time if it is dispatched in time to reach its destination on the day next after the day of dishonour.