Will claim for a policy holder be denied if he start smoking after 5 year of policy and the policy is for nonsmoker?

I assume that you are talking about a life insurance policy or perhaps even a health insurance policy of some kind. The answer is the same either way. As all insurance companies are legal contracts the agreements are based on the conditions at the time the contracts were signed. The insurance company will not penalize anyone who starts smoking after the policy was issued. They will even reduce your rates and give you non-smoker rates if you quit smoking and can prove that you stay quit for a period of one year. The insurance company can provide testing to verify such. Both policies are the same as far as rates. Your price will not increase if you start smoking either.