Negotiable Instruments Act, 1881
106. Reasonable time of giving notice of dishonor
If the holder and the party to whom notice of dishonor 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 dishonor.
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 date next after the day of dishonor.