The longest irrigation canal in India is the Indira Gandhi Canal, also known as the Rajasthan Canal. It is located in the northwestern state of Rajasthan and was completed in 1987.

The Indira Gandhi Canal is an engineering marvel, stretching over 650 km from the Harike Barrage in Punjab to the Thar Desert in Rajasthan. The canal was constructed with the primary objective of providing water for irrigation to the arid regions of western Rajasthan, which had been plagued by drought and water scarcity for centuries.

The construction of the canal was a massive undertaking, involving the excavation of over 20 million cubic meters of earth and the construction of numerous dams, weirs, and other structures. The canal is fed by the waters of the Sutlej River, which is diverted into the canal at the Harike Barrage in Punjab.

The Indira Gandhi Canal has been a game-changer for agriculture in western Rajasthan, transforming vast tracts of barren land into fertile agricultural fields. The canal has facilitated the growth of a wide range of crops, including wheat, mustard, cotton, and sugarcane, and has enabled farmers to cultivate their lands throughout the year.

In addition to providing water for irrigation, the Indira Gandhi Canal has also had a significant impact on the social and economic development of the region. The canal has generated employment opportunities for thousands of people, both during its construction and in the operation and maintenance of the canal and its associated infrastructure.

The canal has also helped to improve the living standards of people in the region, by providing a reliable source of water for drinking and domestic use. This has helped to reduce the incidence of water-borne diseases and improve the overall health and well-being of the people living in the region.

In conclusion, the Indira Gandhi Canal is the longest irrigation canal in India, stretching over 650 km from the Harike Barrage in Punjab to the Thar Desert in Rajasthan. The canal has played a critical role in transforming the arid regions of western Rajasthan, providing water for irrigation, facilitating agricultural growth, generating employment opportunities, and improving the overall living standards of people in the region.