Health Insurance policy issued to you is valid in India only. When you travel out of India then you need Overseas Travel Health insurance policy because of following reasons :
i. If Hospitalization is required while you are in a foreign country then treatment may not start in a hospital; unless you make the payment in cash or by credit card or produce health insurance policy reference / card.
ii. Some embassies of foreign countries need it as part of documents for issue of visa itself. An example is the Germany Embassy or Spain Embassy.
Even though this policy in the beginning was for taking care of hospitalization/medical treatment only but at present this product is available with certain additional features.
You will notice that while in the case of Health Insurance policy valid with in India is having the limit of Rs 5,00,000 but in case of Overseas Health Insurance policy sum can be as high as US$ 5,00,000, which is nearly equal to Rs. 235 lakhs. (Rs 2.35 crores)
Health Insurance policy valid within India is issued with difficulty for those above 60 years in age. In the case of Overseas Travel Health Insurance for India, the policy can be issued even for the age of 84 years but subject to following documents being attached with proposal form for all those whose age is above 70