My company (Adamjee) deals like this:
Lower of sum insured or market value.
Incase you have sum insured 30lacs and market value at time of theft/total loss/snatching is say 33lacs, then you will get compensated for almost full 30lacs
Or
If at time of loss, the market value is say 28 lacs, then you get around 28 lacs (lower of)
There is absolutely NO depreciation incase of theft or total loss..