No one in the slum of Murtinagar wants to play with Temri and Chinna. The brother and sister don’t speak the local Hindi or Marathi languages – they came here, to Mumbai, India’s financial capital, 10 days ago from their village, Andhra, and grew up speaking the regional language of Telegu. Jaya Kummari, their mother, brought Chinna and Temri to Mumbai because of a drought that has left Andhra without water.

In the corner of the one-bedroom apartment that their parents are renting for 4,000 rupees (£40) a month, Temri and Chinna play board games. “We miss our friends,” Chinna says.

The children are missing school and keep asking their mother when they can go home. “What are we supposed to do?” Jaya says. “There’s not even water to drink.”

The Kummaris are rice farmers. Rice is a water-intensive crop; it takes more than 2,500 litres of water to produce one kilo (pdf). Usually the Kummaris can harvest their crop twice a year but, since the drought, they’ve suffered enormous financial losses. “No one in the village had water,” Kummari says. “We had no choice but to come here.”

The drought has affected 330 million people in India this year, according to government figures. About 15% of India’s gross domestic product comes from agriculture and 68% of the 1.3 billion population are farmers. With no water for irrigation, the drought has been devastating for farmers. Like the Kummaris, hundreds of families have had to leave their lands in search of water.

Extreme weather linked to climate change is becoming increasingly common in India. Last year, hundreds of people were killed by floods in Chennai, a city on the Bay of Bengal in eastern India.

In the western state of Maharashtra, one of the worst-hit regions, 9 million farmers have little or no access to water. This year, at least 216 farmers have committed suicide in the state.

The government’s response has been slow and inefficient. After weeks of waiting, trains carrying thousands of litres of water reached the region of Marathwada this week, where rivers have dried up and dams are holding about 3% of their capacity. Many other drought-hit regions are still waiting for deliveries.

The government introduced a $1.3bn (£890m) crop insurance scheme this year, but only 19% of farmers have signed up. A few weeks ago, the prime minister, Narendra Modi, said: “We are working on a big scheme to bring water to farmlands. We need to have a permanent solution to the drought,” as he addressed a rally in the eastern state of Assam ahead of state elections.

Across the country, schools in many villages have closed. In some places, doctors have postponed surgeries saying they don’t have water to wash their hands after procedures. With no harvest and no water, villagers are flocking to cities, where water is more easily available.

People collect water from a tanker in Bhiwandi, on the outskirts of Mumbai. Photograph: Divyakant Solanki/EPA

The drought migrants have no homes in the city; some have made makeshift shelters on construction sites, footpaths and park benches. The villagers have no work and no cash, and many are forced to beg. The rural exodus is becoming a burden for authorities in Mumbai, who say they need help to provide food, shelter and jobs to the displaced people.

The Kummaris were luckier than many others. Jaya’s husband found part-time work as a driver, but the couple can barely afford rent, and savings are running out. “We lost everything because of the drought,” she says. “It’s been like this for the last two years. Nothing is growing on our land.”

Scarcity has made water even more precious. In the north, in states such as Punjab and Haryana, local governments are fighting for control of rivers. Rioters in Haryana cut off the water supply to Delhi earlier this year until their demands were met, signalling that control over resources is a serious political issue.

In Mumbai, water is more easily accessible, though, even here, only wealthier parts of the city have 24-hour supply. In the settlement of Murtinagar, the pipes only deliver water between 10.30am and 1pm. As soon as the water starts to flow, the slum comes alive and people rush to the pipes to fill up their plastic containers so they have enough for the day.

For Kummari, the few bucketfuls of water are a blessing. She fills up several containers so the family have enough to bathe, drink and cook. “At least we have this much,” she says. “We will treat it like a gift from God.”