No, an Insurer cannot decline to renew your policy.
IRDA vide its circular 52/15/IRDA/Health/SN/08-09 has advised Insurers to not deny renewal of policy on any grounds other than fraud, moral hazard and misrepresentation.
An Insurer can, however, deny renewal of a policy when the Insurer has decided to close that particular product. Closure of a product could be dictated by business considerations i.e. aspects like profitability, serviceability. But even when an Insurer does decide to close a product, they have to make provisions for a replacement product and accord a suitable time for the Insured to make alternate arrangements.