Section 49 of IPC 1860: Year, Month

Year, Month-Indian Penal Code
Wherever the word year or the word month is used, it is to be understood that the year or the month is to be reckoned according to the British calendar.
All Article, Acts at one Place
Wherever the word year or the word month is used, it is to be understood that the year or the month is to be reckoned according to the British calendar.