Millions of people are turning to water tank trucks in the southern Indian state of Tamil Nadu as house and hotel taps run dry because of an acute water shortage caused by drying lakes and depleted groundwater.

State Rural Development Minister S.P. Velumani said on Wednesday that the drought followed a 62 per cent shortfall in monsoon rains last year compared to 2017.

People are lining up for water cans in the state capital, Chennai.

Hotels in the southeastern city of 4.6 million are rationing water for guests amid searing heat.

A shepherd walks with his livestock at the dried out Puzhal reservoir on the outskirts of Chennai. Water levels in the city's four main reservoirs have fallen to some of their lowest levels in decades. (Arun Sankar/AFP/Getty Images)

All four reservoirs that supply Chennai, known as the Detroit of south Asia for its flourishing automobile industry, have run dry this summer, largely because of poor monsoon rains last year.

Chennai is one of 21 cities that a government think-tank warned last year could run out of ground water by 2020. This year's monsoon is delayed, further compounding problems across a swath of western and central India.

Water storage levels in the city's four major reservoirs were one-hundredth of what they were this time last year — and at a mere 0.2 per cent of capacity, according to state government data.

People in New Delhi are also being forced to rely on tankers delivering water amid a searing heat wave. (Anushree Fadnavis/Reuters)

Some companies have asked employees to work from home. Some restaurants are closing early and even considering not serving lunch if the water scarcity worsens.

Gauri Shankar, general manager of Hotel Deccan Plaza in Chennai, said two tank trucks bring water to the hotel every day from a town 60 kilometres away at a cost of 4,000 rupees ($76) each.

"Even a water tanker is proving difficult to get in the city. We are getting our supply because we entered into a contract with a supplier in September as the water taps started going dry," Shankar said by phone.

Women fetch water from an opening made by residents at a dried-up lake in Chennai. (P. Ravikumar/Reuters)

Top elected official K. Palaniswami said the state has diminishing groundwater supplies and has asked other states for spare water until October's monsoon rains.

Monsoons reach different parts of India at different times.

Northern and eastern India have experienced heat waves with temperatures soaring to 48 Celsius amid a delayed monsoon. At least 90 people have died due to heat stroke in the eastern state of Bihar since June, according to the state disaster management department.

This year's monsoon arrived in the southern state of Kerala a week late and slowly started moving to other parts of country.

India is facing a 43 per cent shortfall in monsoon rains across the country because of its late arrival, according to the India Meteorological Department.

Meteorologists said monsoon rains usually cover two-thirds of the country by mid-June. However, they currently have reached less than half that area. But the monsoon's progress is expected to pick up in the next 10 days.