Byelections in Tamil Nadu, West Bengal, Puducherry and Assam will be held on October 6, with counting scheduled for October 9.

The Election Commission announced the schedule on September 8. The byelections will fill vacant assembly seats in the four states and Union Territory.

Campaigning has picked up in the constituencies going to the polls. Local issues are expected to dominate the contests.

The results on October 9 will be watched as a mid-term signal of voter mood in each region. Parties have fielded senior campaigners in key seats.

Voter turnout will be a key number to watch. Byelections often see lower participation than general elections.

The Election Commission has said all polling arrangements, including security and electronic voting machines, are in place for the October 6 vote.

Each byelection fills a seat that fell vacant mid-term. The winners will serve out the remaining term of the assembly.

Political parties see these contests as a test of their ground organisation. Strong booth-level work often decides byelections more than big rallies.