HRA Deduction - employee produced rent receipts for his stays at rental house in Thane (which is a non-metro city)

Hi all, please help me out. Our company is situated in Mumbai, and we are providing HRA deduction to all employees at 50% of basic salary as per income tax laws. Since Mumbai is a metro city, now one of the employees has produced rent receipts for his stay at a rental house in Thane (which is a non-metro city).

Please let me know whether we should give him a deduction of HRA at 50% of basic salary (as our company is in a metro city) or whether we should give him a deduction of HRA at 40% of basic salary (as he is from Thane, a non-metro city).

Please help me, it's urgent.

Dear Beauty_babu & PON 1965,

I am asking about THANE district, such as Dombivali, Kalyan, etc. What about Kalyan, Ulhasnagar, etc. Please reply.

Regards,
Rajendra V

Can anyone provide me with the list of metro cities in India (ideally from a government document)?