A pair of conjoined twins wore dark glasses so they could not see who the other voted for as they cast ballots for the first time in northern India.

Sohan and Mohan Singh, 19, are joined at the hip and share several organs as well as legs. They live in a charitable home after being abandoned at birth.

Wearing colourful checked shirts and matching black turbans, the brothers cast their votes on Sunday in state elections in Punjab.

"I felt really nice. They made good arrangements for us to vote," Sohan told AFP on Monday from the holy city of Amritsar where they live.

"We were given dark glasses so that we could not see who we voted for inside the polling booth." 

India, the world's largest democracy, follows a secret ballot system to ensure free and fair elections, with all citizens above 18 years eligible to vote.

The duo, who were issued separate electoral cards, were garlanded and handed certificates by officials as they emerged from the polling station.

The teenagers flashed their inked fingers while encouraging others to come out and vote.

The Singh brothers work in the state power department but draw just one salary. 

They did not opt for surgery to separate them as there was risk of one of them dying, Sohan said.

"There is no choice. I can't afford to lose him," he said. 

Punjab is one of the five states where polling is being held to elect new assemblies.