Vote counting for bypolls in 13 states and one union territory in progress.
The bypolls to 29 assembly seats and three Lok Sabha seats led to marginal gains for the BJP, which won eight seats - up from six. But it suffered setbacks in Himachal Pradesh and Bengal. The Congress retained 9 seats and won big in Himachal.
Here are ten points on this big story:
The BJP swept the board in the northeast, winning all nine seats along with its allies. Of the five seats in Assam, the party won all three where it fielded candidates. Alliance partner UPPL won the other two. It also posted victories in Mizoram and Meghalaya.
The Congress sprung a surprise victory in Himachal Pradesh, wresting two BJP seats in the state and one in Karnataka. In Himachal Pradesh, the Congress retained Fatehpur and Arki and posted a win in BJP-held Jubbal-Kotkhai. It also bagged the Lok Sabha seat of Mandi.
The Trinamool Congress continued its winning streak, sweeping the bypolls in all four seats of Bengal. In three seats, the BJP candidates lost their deposit. The BJP lost two of the seats it held - Dinhata and Santipur. It was a setback for the party which is currently grappling with an exodus of MLAs and senior leaders after the Trinamool's sweeping victory in the April-May state polls.
Assam Chief Minister Himanta Biswa Sarma attributed the NDA victory in the northeast to Prime Minister Narendra Modi's development initiative. "This victory in Assam is not a normal victory... In many seats and Union Territories, there has been a record margin win for the BJP and the NDA," he said.
Congress's Rahul Gandhi hailed the party's victory, tweeting, "Every victory for the Congress is a victory of our party worker. Keep fighting hate. No fear!".
In Mandi, Himachal Pradesh, Pratibha Singh, the wife of late chief minister Virbhadra Singh, beat the BJP's Kargil war hero Brigadier (retired) Khushal Thakur. BJP candidate Gyaneshwar Patil won in the Khandwa Lok Sabha seat in Madhya Pradesh. The Shiv Sena's Kalaben Delkar won the Dadra and Nagar Haveli seat.
In Bihar, Nitish Kumar's Janata Dal United won both seats. INLD'S Abhay Chautala won his traditional stronghold Ellenabad.
In Rajasthan, where the election is seen as a referendum on the performance of the Ashok Gehlot government, the Congress won Vallabhnagar and Dhariawad.
In bittersweet results for Karnataka Chief Minister Basavaraj Bommai, the ruling BJP won the Sindgi assembly segment, but suffered a shock defeat to the Congress in Hangal.
"Elections are won and lost... these by-elections are fought on particular time and issues, and its outcome is not a complete verdict. However, I have taken this election setback very seriously and we will do all the corrections," Mr Bommai said.
