It is possible to keep a body intact by using certain chemical ingredients. Mummification is also a chemical procedure through which people in ancient Egypt preserved the bodies of pharaohs whereas in fact most of the pharaohs were the worst and most oppressive people of their time. Some of them went as far as to claim to be deities. Prophet Moses (AS) lived in the period of one such pharaoh who claimed to be the superior god of the people of Egypt. The Quran quotes Pharaoh who said to Moses:
«فَقَالَ أَنَا رَبُّکُمُ الْأَعْلىَ‏»
And (Pharaoh) proclaimed: "I (Pharaoh) am your Lord the Highest."[1]
Hence, if a body remains intact and does not decompose, it is not the sign of a religion being true or an individual being good. Therefore, it is likely that a body does not decompose after death even in India or other countries. The bodies may be mummified or some chemical elements might be used to preserve them with the intention attracting ordinary people to their religions.
It should be noted that over the history, the bodies of some people remained intact in the graves for many years to serve as miracles or in order for others to draw lessons from them but such cases are few and far between and we cannot speak of it as a general rule.
The latest such incident was the body of martyr Muhammad Reza Shafe'i from the province of Qom (Iran) who had been taken prisoner of war in the imposed Iran-Iraq war. He was martyred in Iraq and buried there. After many years, his grave was excavated and his body exhumed and it was found completely intact and was sent to Iran in a prisoner swap.[2]
For further information, read: The bodies of certain martyrs not decomposing, answer 19508.

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