Apartment security guard drinking alcohol when on duty

Dear Experts,

I have recently purchased a 15 year old (second hand) flat in Bangalore.

One of the security guards is always found to be drunk / drinking when on duty and the association along with a few residents takes this very lightly. What is the law to manage such issues with the guard / security agency / association? Is it legal to drink when on duty in any profession? Please share some light on this subject.

Thanks,

Manjunath