In UP, which has 80 Lok Sabha seats and where the BJP did exceedingly well in 2014 elections by winning 71 seats on its own (two were won by its ally Apna Dal), the party faces combined challenge of the Samajwadi Party, the Bahujan Samaj Party and the Rashtriya Lok Dal. These three parties have forged an alliance to take on the BJP. The Congress, which is fighting the polls on its own in the state, has also injected new energy in its efforts by appointing Priyanka Gandhi Vadra as general secretary incharge of eastern UP.
In Bihar that elects 40 MPs, the ruling alliance of the BJP, the Janata Dal-United and the Lok Janshakti Party faces a tough contest with a combined opposition that includes the Rashtriya Janata Dal, the Congress, the Rashtriya Lok Samata Party, the Hindustani Awami Morcha and some other parties.
The BJP has been paying a lot of focus to West Bengal to emerge as the main opponent of the ruling Trinamool Congress. The party is hoping to improve its performance beyond the two Lok Sabha seats it won in the state in 2014.
Here's how Uttar Pradesh, Bihar and West Bengal will vote
Uttar Pradesh:
April 11: Saharanpur, Kairana, Muzaffarnagar, Bijnor, Meerut, Baghpat, Ghaziabad, Gautam Buddha Nagar
April 18: Nagina, Amroha, Bulandshahr, Aligarh, Hathras, Mathura, Agra, Fatehpur Sikri
April 23: Moradabad, Rampur, Sambhal, Firozabad, Mainpuri, Etah, Badaun, Aonla, Bareilly, Pilibhit
April 29: Shahjahanpur, Kheri, Hardoi, Misrikh, Unnao, Farrukhabad, Etawah, Kannauj, Kanpur, Akbarpur, Jalaun, Jhansi, Hamirpur
May 6: Dhaurahra, Sitapur, Mohanlalganj, Lucknow, Rae Bareli, Amethi, Banda, Fatehpur, Kaushambi, Barabanki, Faizabad, Bahraich, Kaiserganj, Gonda
May 12: Sultanpur, Pratapgarh, Phulpur, Allahabad, Ambedkar Nagar, Shrawasti, Domariyaganj, Basti, Sant Kabir Nagar, Lalganj, Azamgarh, Jaunpur, Machhlishahr, Bhadohi
May 19: Maharajganj, Gorakhpur, Kushi Nagar, Deoria, Bansgaon, Ghosi, Salempur, Ballia, Ghazipur, Chandauli, Varanasi, Mirzapur, Robertsganj
Bihar:
April 11: Aurangabad, Gaya, Nawada, Jamui
April 18: Kishanganj, Katihar, Purnia, Bhagalpur, Banka
April 23: Jhanjarpur, Supaul, Araria, Madhepur, Khagaria
April 29: Dharbhanga, Ujiarpur, Samastipur, Begusarai, Munger
May 6: Sitamarhi, Madhubani, Muzaffarpur, Saran, Hajipur
May 12: Valmiki Nagar, Paschim Champaran, Purvu Champaran, Sheohar, Vaishali, Gopalganj, Siwan, Maharajganj
May 19: Nalanda, Patna Sahib, Pataliputra, Arrah, Buxar, Sasaram, Karakat, Jahanabad
West Bengal:
April 11: Coochbehar, Alipurduars
April 18: Jalpaiguri, Darjeeling, Raiganj
April 23: Balurghat, Maldaha Uttar, Maldaha Dakshin, Jangipur, Murshidabad
April 29: Baharampur, Krishnanagar, Ranaghat, Bardhaman Purba, Bardhaman - Durgapur, Asansol, Bolpur, Birbhum
May 6: Bangaon, Barrackpur, Howrah, Uluberia, Sreerampur, Hooghly, Arambag
May 12: Tamluk, Kanthi, Ghatal, Jhargram, Medinipur, Purulia, Bankura, Bishnupur
May 19: Dum Dum, Barasat, Basirhat, Jaynagar, Mathurapur, Diamond Harbour, Jadavpur, Kolkata Dakshin, Kolkata Uttar