NEW DELHI, May 28 (Xinhua) -- By-elections are being held in India on Monday in as many as four parliamentary constituencies and 10 state Assembly constituencies across 10 Indian states.

Out of the four parliamentary constituencies, two are in southwestern state of Maharashtra, and one each in northern Uttar Pradesh and northeastern state of Nagaland.

The elections assume significance as their outcome would set the tone for the next general elections, scheduled to be held early next year.

Though, speculations are rife in the political circles that the general elections might be postponed to the year-end along with state Assembly polls in four states.

Out of the 10 state Assembly constituencies where by-polls are held on Monday, two are in eastern state of Jharkhand, and one Assembly constituency each in Maharashtra, Uttar Pradesh, Kerala, Punjab, West Bengal, Uttarakhand, Meghalaya, and Bihar.

The by-elections became a necessity either due to death of the legislators, or their resignations.

An intense battle is being witnessed in Uttar Pradesh's Kairana parliamentary constituency where the ruling Bharatiya Janata Party's (BJP) candidate is pitted against a joint candidate of four opposition parties namely Samajwadi Party (SP), Bahujan Samaj Party (BSP), Rashtriya Lok Dal (RLD) and the Indian National Congress (INC).

Counting of votes of the by-elections will be held on May 31.