"It's my humble appeal to the Prime Minister... We want that all the files pertaining to his death must be declassified," Sunil, who is a BJP leader, said.
Lal Bahadur Shastri died in Tashkent on January 11, 1966 at the age of 61 soon after signing the Tashkent Pact with Pakistan. It was maintained that Shastri had died of cardiac arrest but his family had alleged foul play.
"Wherever I go every second person who meets me asks me about what happened to Shastriji, how he died," Sunil, a former Rajya Sabha MP, said.
He said he had made a similar appeal three times to the previous Manmohan Singh government but nothing was done.
"The air must be cleared on the issue at the earliest as the whole nation wants to know what all happened to the second Prime Minister of this country, a day after the signing of Tashkent declaration," Sunil said.