While NDTV-Indian Express opinion poll telecast Monday night projects the NDA falling short of majority mark of 272 seats with a tally of 245-265 seats, Congress and allies are likely to get 180-200 seats and others 95-115.

However, the opinion polls conducted by Star News in association with two leading newspapers and a marketing research agency gives the NDA a slender majority with 279 seats in the 543-strong Lok Sabha. The poll gave Congress-led alliance 169-181 seats and others 88-100 seats.

With exit polls after the April 26 round of polling and the latest opinion polls broadcast late on Monday night forecasting a hung parliament, the BJP cannot afford to slip from its previous position in the 83 constituencies most of which are in the Hindi-speaking areas. The party has a commanding position there.

Under the watchful eyes of over 100,000 security personnel, an estimated 10.72 crore voters are expected to exercise franchise in the fourth phase in seven states to decide the electoral fates of 921 candidates including Prime Minister Atal Behari Vajpayee contesting from his traditional constituency of Lucknow.

Vajpayee is being challenged in Lucknow by his former cabinet and legal luminary Ram Jethmalani, an independent candidate backed by Sonia Gandhi-led Congress party and nominees of Samajwadi Party and Bahujan Samaj Party.

An opinion poll of Zee News said Monday night Vajpayee will secure an "overwhelming" victory in Lucknow and the recent killing of 22 women in a stampede during a sari giveaway function with a senior BJP leader there would not affect much BJP's prospects in the constituency.

The poll conducted among 446 voters representing a cross-section of people in Lucknow and 72 percent of them says Vajpayee will be winner while 26 percent favoured Jethmalani.

The main point of interest in the electoral battle in Lucknow, capital of Uttar Pradesh, is whether Vajpayee's winning margin will go up, remain in tact or come down in a constituency which has 23 percent Muslim voters.

Besides Vajpayee himself, all senior leaders of BJP and film stars like Bollywood heart-throb Vivek Oberoi and his actor father Suresh Oberoi have campaigned in Lucknow which the prime minister has represented four times in the past.

Vajpayee called elections six months early to cash in on his personal popularity, a strong economy, improving ties with old foe Pakistan and a bumper harvest, Reuters reports.

Instead, his party's "India Shining" campaign has failed to resonate among the millions of impoverished rural masses who feel left out of India's economic boom.

Opinion and exit polls after the third round rattled the BJP because they showed it struggling to retain a majority and the main opposition Congress party doing far better than predicted.

A key constituency in today's polling will be Madhepura, the second constituency from where Bihar strongman Laloo Yadav is trying his luck after Chapra on April 26 when he crossed swords with India's Civil Aviation Minister Rajiv Pratap Rudy of BJP.

But allegations of widespread electoral fraud and violence marred the polling in Chapra prompting BJP, Samajwadi Party and BSP to demand fresh poll in the entire constituency. Yadav denied the charges of rigging and violence and an Election Commission team which completed its probe in Chapra is likely to take a decision later this week on the demand for countermanding of elections in the constituency.

The staggered Indian elections that began on April 20 would end on May 10 when the largest chunk of 183 parliamentary seats will go to poll. The counting is slated for May 13.