Notice Of Change

if we made any changes in working hours of emoloyees who are working in the factory, is their any rule that we need to take take approval or permission from inspector of factories?

You need to follow the requirements of Industrial Dispute Act and Standing Orders for making changes in work times.
Since this amounts to change in conditions of employment, you will need approval of the workers or their union.
You also need to intimate the change to the factory inspector.

Dear Ramesh,
Reference: Factories Act-1948, Tamilnadu Factories Rules - 1950 under section - 61 (1) (9) with Rule 79.
You must update your shift and work timings in Form - 11(Notice of Period of Adult Workers and Childrens) and send (2 forms) to Inspector of Factories for approval. The approved copy will be send back to you from DCIF Office.
Then, you should display this form-11 at your main notice board.