The Commonwealth Parliamentary Association (formerly known as the Empire Parliamentary Association) was established in 1911 under the aegis of the erstwhile British Empire. It has held its flagship event- the Commonwealth Parliamentary Conference- annually since 1961 (prior to this, the conference was a biennial event).
The Commonwealth Parliamentary Conference is the largest gathering of Commonwealth Parliamentarians who come together to discuss and debate key global political issues and developments.
The 37th Commonwealth Parliamentary Conference was hosted by India in the year 1991. To commemorate the occasion, the Reserve Bank of India issued a Re. 1 coin that has a cupro-nickel composition (as seen in the photo below). The coin in the photo below bears a diamond mint mark below the year '1991', signifying that it was minted in Mumbai.