India 1 Rupee Big Coin 1982 Mumbai Mint

This is a 1 Rupee coin from the Republic of India, issued in 1982. 

Composition: The coin is made of a copper-nickel alloy. 
Design: The reverse side shown features the denomination "1" flanked by two stalks of wheat or grain, with "RUPEE" and the year "1982" below. "रुपया" is also inscribed in Hindi above the "1". 
Size: This specific issue is known as the "big size" or "heavy coin" version, with a diameter of 28 mm, which was larger than subsequent 1 rupee coins.