Is there any mediclaim policy which covers deceases at the start of policy period.

I am hoping you mean Diseases not deceases, meaning ceases to be alive, if so you should have no issues with health insurance. Corpses are rarely if ever covered. But going to your question as I assume you meant to ask. Many insurance plans do not have a pre exist clause in them at all or are specific to only one or two different diseases. Many individual plans you purchases DO have pre exist clauses especially if you have not had insurance for a length of time before purchasing the plan. A pre exist is almost always a timed thing.(typically they will take whatever diagnosis code you are submitting and search your medical record back a specified amount of time typically 6 months to a year to see if you have had that same diagnosis code before) Meaning if asthma was in a pre exist clause and you have it, you have to wait x amount of time and pay for all costs related to it at 100% through that time. After that time you would be covered like anything else in your plan. Pre exist clauses can be worded very unusually and quite confusing but they are not always as a bad thing as they seem. Call your insurance companies customer service and they can walk you through the specifics