I presume you are enquiring about getting health insurance for your parents in India. All four Govt owned insurance companies viz. United Insurance, National Insurance. New India Insurance & Oriental Insurance issue health insurance policy for people who want to cover themselves for the hospitalization & other major medical expenses. These policies do not cover routine visits to the doctor. One must go to an approved medical facility/ hospital for the treatment. The health insurance business in India is in its infancy. Not many people buy it due to the limitation and bureaucratic delays in payment of bills etc. However, the insurance companies are now tying up with many prestigious hospital groups like Apollo. This is motivating many seniors and also private sector executives who do not have employer paid medical benefit plans to buy medical insurance. Yoy may ask your parents to enquire from any of the above insurance companies which have branches in almost all district headquarters in India.
If you are enquiring about Visitors Medical Insurance, these companies also issue policies covering short overseas visits. the cost is much less than buying the visitors insurance here in USA. There are several deductible options. Higher the deductible, lower the premium. For a parent of 65 years age with no prior history of major illness & no existing major health condition, the cost of six months' insurance could be as low as Rs 10,000 with deductible of $200 (For USA Visit) The cost varies for the country you are visiting because the health care costs have a wide variance.
Hope this helps.