I think that your registered office/ head office is situated at a different location from your factory. If it falls within the area where the West Bengal Shops and Establishment is applicable your Leave Policy for the employees should be formulated in such a way that the types of leave and their quantum in a year should not be less than what are prescribed under that Law. If any statutory approval of the festival holidays ( probably described in the post as calendar holiday ) is required, it shall also be complied with accordingly. But remember that since the grant of such leave and holidays are already in vogue, you should not reduce them.
From India, Salem