Altogether 678,898 electors will decide the fate of 20 candidates in four Assembly constituencies in Assam on Monday.

Ground reports suggest that a keen contest is on the cards between the ruling BJP and Opposition Congress at Ratabari, Rangapara and Sonari Assembly constituencies, all held by the BJP, and between the Congress and the AIUDF in Jania, held by the Congress.

The polling will take place from 7am to 5pm.

Of the electorate, 351,094 are men and 327,803 women. There is one third gender elector in Jania.

Assam chief electoral officer Mukesh Sahu on Sunday appealed to all the voters to exercise their franchise to strengthen the spirit of democracy. “We appeal to everyone to cast their votes,” said Sahu.

He added that all presiding officers, along with other staff, reached their respective polling stations on Sunday.

Sahu said some polling stations were identified as sensitive and all possible measures have been taken to conduct the elections fairly. He, however, did not name the number of sensitive stations.

The Election Commission has set up 830 polling stations — 202 in Ratabari, 229 in Jania, 197 in Rangapara and 202 in Sonari.

The bypolls were necessitated in the four constituencies after their representatives — Topon Kumar Gogoi (Sonari), Pallab Lochan Das (Rangapara), Abdul Khaleque (Jania) and Rajdeep Roy (Ratabari) — were elected to the Lok Sabha.

The Congress and the BJP had used the four MPs to spearhead election campaigns in the Assembly constituencies they had represented till a few months ago.

The campaign, which drew to a close on Saturday, witnessed all state party leaders of different parties slamming their opponents and offering a plethora of promises to woo voters. Barring Congress in-charge Harish Rawat, no national leaders took part in the campaign.

Four crorepatis, including two from the tea tribe, are fighting the election.

While two crorepatis — Rajen Borthakur (BJP) and Kartik Kurmi (Congress) — are fighting it out for Rangapara constituency, two others, Sushil Kumar Suri (Congress) and Nabanita Handique (BJP), are in the fray in Sonari.

The BJP’s Sonari candidate, Nabanita Handique, is the only woman candidate in the bypoll.

Barring Jania, which is dominated by minorities, the other three constituencies have a sizeable tea tribe population, prompting the Congress to field three tea tribe candidates.

The BJP was also seen banking on its development activities for the tea garden community.

The Congress on Sunday also appealed to the people to come out and cast their votes.

A senior police official here said all possible measures have been taken to thwart any untoward incident on Monday. “We have adequate force for the election day. Violence is unlikely during polling time. However, we are keeping a strict vigil so that the bypolls pass off peacefully.”

Union minister of state for home Kishan Reddy was in the state on Sunday, taking part in different programmes. He will be in the Northeast till Tuesday.

On Monday, Reddy will meet governor Jagdish Mukhi and chief minister Sarbananda Sonowal, besides attending a programme at BSF frontier headquarters at Patgaon and another at the 4th Assam Police Battalion, Kahilipara, here.