The Trinamool Congress won in West Bengal and the Jharkhand Mukti Morcha (JMM) emerged victorious in Jharkhand.

As the results for the Sunday assembly by-polls, held also in Himachal, Assam and Rajasthan, were announced, Prime Minister Narendra Modi, in a victory tweet, said: "I thank the people for the constant support, blessings and unwavering faith in politics of development and good governance" agenda of the BJP.

The ruling Aam Aadmi Party (AAP) in Delhi -- where it won 67 out of 70 assembly seats in the 2015 elections -- suffered a humiliating defeat in Rajouri Garden assembly constituency and figured at a distant third after the BJP and the Congress.

Manjinder Singh Sirsa (BJP) defeated Meenakshi Chandela of the Congress by a margin of nearly 14,000 votes, according to the Election Commission.

Sirsa garnered 40,602 votes, Chandela 25,950 and the AAP's Harjeet Singh 10,243 out of a total 78,091 votes polled. The seat fell vacant after AAP's Jarnail Singh quit to contest in the Punjab assembly polls in February earlier this year.

AAP leader and Delhi's Deputy Chief Minister Manish Sisodia said the voters were angry over Jarnail Singh's Punjab switchover, which led to the party's poor show. "We tried to make them understand, but it seems they are still angry with the AAP."

The BJP, which had so far only three members in the House, said the AAP's loss had put it "on the verge of extinction".

In Himachal Pradesh, the opposition BJP retained its stronghold Bhoranj assembly seat for the seventh consecutive term. Anil Dhiman defeated Promila Devi of the Congress by a margin of 8,290 votes.

The ruling BJP in Madhya Pradesh won from Bandhavgarh and the Congress in Ater.

The poll panel said BJP's Shivnarayan Singh defeated Savitri Singh of the Congress by 25,476 votes in Bandhavgarh.

In Ater, the Congress' Hemant Katare defeated BJP's Arvind Singh Bhadoria by a little over 800 votes to retain the seat.

In Assam, the BJP retained the Dhemaji assembly seat with Ranoj Pegu defeating Babul Sonowal of the Congress by a margin of over 9,000 votes. Pegu polled 75,217 votes, Sonowal 65,932 votes and Jadu Hazarika of the CPI-M 4,944 votes out of the total 148,658 polled.

In West Bengal, the ruling Trinamool Congress triumphed in the Kanthi Dakshin assembly constituency, saying it was a reaffirmation of the people's faith in Chief Minister Mamata Banerjee's developmental agenda. Chandrima Bhattacharya defeated Sourindra Mohan Jana of the BJP by a margin of 42,526 votes.

The BJP, however, said it was "happy" with the outcome reflecting it was growing in popularity in the state.

"We expected the result to be a bit better. People came out to vote for us amid the atmosphere of terror created by the ruling party," Jana said. The results showed the BJP's vote share has gone up by around 22 per cent compared to the assembly polls last year.

Communist Party of India candidate Uttam Pradhan, who had finished second in 2016, lost his security deposit this time. The Congress also put up a poor show, with its nominee Nabakumar Chanda getting only around 1.3 per cent of the votes.

The Congress, however, got consolation in Karnataka where it won Nanjangud and Gundlupet assembly constituencies defeating BJP candidates at both places.

In Jharkhand's Littipara, Simon Marandi of the JMM defeated Hemlal Murmu of the BJP by 12,900 votes.