Kolkata: Against the backdrop of a battle of nerves between the Election Commission and West Bengal's ruling Trinamool Congress, 56 assembly constituencies go to the hustings on Sunday, mostly covering a region where the newly formed Left Front-Congress alliance is hoping to come up with its strongest showing.

From the picturesque hill station of Darjeeling in the northern tip to Malda -- famous for its mouth-watering mangoes -- and down south to Birbhum, nearly 1.22 crore (1,21,74,947) voters in six districts are eligible to elect their nominees across 13,645 polling stations from a field of 383 candidates -- 33 of them female -- in the second phase.

Five of the constituencies are in Alipurduar district, seven in Jalpaiguri, nine in North Dinajpur, six each in Darjeeling and South Dinajpur and 12 in Malda.

The only south Bengal district with 11 constituencies going the polls in this phase is Birbhum -- that houses Visva Bharati University set up by Asia's first Nobel laureate poet Rabindra Nath Tagore.

But Birbhum has now grabbed national attention for a reason far removed from Tagore's ideals.

The district's controversial Trinamool Congress chief Anubrata Mondal -- known for making inflammatory speeches and repeatedly accused by the opposition of using strong-arm tactics to turn all elections in the district into a "farce" over the past three years -- has been kept under "constant watch" of central police forces and a local magistrate by the Election Commission in a bid to hold free and fair polls.

The EC has also show-caused Mondal's mentor and Chief Minister Mamata Banerjee for announcing at a poll rally that Asansol in Burdwan district would be upgraded into a new district.

Riled by the EC strictures, Banerjee has gone all guns blazing at the constitutional body, accusing it of acting at the behest of the Congress, Bharatiya Janata Party and the CPI-M.

However, this phase is the most crucial for the Left Front-Congress alliance, particularly in the 45 northern Bengal seats.

In elections held in the recent past, the combine's vote percentage far outshoots that of the Trinamool in most of the constituencies.

And in its bid to capture power in the state, a superb performance in north Bengal is a must for the opposition team.

But on the flip side, there are at least five seats where Left Front partners like the Revolutionary Socialist Party and the All India Forward Bloc are locking horns with Congress candidates.

Besides in Birbhum district's Hansan, despite the Left Front announcement that its constituent RCPI would withdraw from the fray in favour of the Congress, the same candidate has entered the race backed by a splinter group of the RCPI.

The BJP-Gorkha Janmukti Morcha combine are contesting all the seats.

The Trinamool has nominated 55 candidates, and has lent support to Harka Bahadur Chettri of the Jan Andolan Party.

The Congress has put up 23 candidates, and the Left Front 34. The alliance has not fielded any candidate in the three seats of the Darjeeling hills -- Darjeeling, Kalimpong and Kurseong -- and has extended support to an independent in English Bazar.

A star constituency is Darjeeling district's Siliguri, where former Indian football captain and Trinamool nominee Baichung Bhutia is pitted against former state minister and CPI-M heavyweight Asok Bhattacharya.

Eyes will also be on Sujapur in Malda district where two relatives of late Congress stalwart A.B.A. Ghani Khan Choudhury -- affectionately called Barkatda -- are locking horns.

Choudhury's younger brother Abu Nasar Khan Choudhury, in the fray as the Trinamool nominee, is contesting against his nephew Isha Khan Choudhury, representing the Congress.

Abu Nasar Khan Choudhury had won the 2011 polls as a Congress candidate but later joined the Trinamool.

Other notable candidates are state ministers Gautam Deb (Dabgram-Pulbari), Krishnendu Narayan Choudhury (English Bazar), Sabitri Mitra (Manikchak) -- all Trinamool Congress, and BJP's actress candidate Locket Chatterjee (Mayureswar).

So far, voters in 49 of the total 294 constituencies have exercised their franchise on two dates -- April 4 and 11 -- that comprised the first phase.

West Bengal is having a staggered six-phase election. Polling for the remaining phases will be held on April 21, 25, 30 and May 5.