(CNN) India's killer heatwave is leaving the country reeling from the worst drought in decades and a rural population struggling to survive.

Relief is due with the arrival of the monsoon in mid-June, and because of the impending La Nina weather pattern , the forecast is for above-average rainfall.

However WaterAid India's Head of Policy, Nitya Jacob, says groundwater levels are so depleted that even if a good monsoon comes in June -- and meteorologists predict there will be one that ends the drought -- it won't be enough.

"Even if the monsoon is good, it cannot compensate," Jacob told CNN.

Central Water Commission data shows that India's major reservoirs are 79% empty , and 75% of India's basins are holding less water than the 10-year average.

CNN Meteorologist, Michael Guy, says this is usually the hottest time for the subcontinent, but this year has seen abnormally high temperatures.

"India is currently in their summer or pre-monsoon season, which lasts from April to late May, or early June," says Guy.

"This year we've seen temperatures range from the lower 40s to as high as 47˚C or 116˚Fahrenheit. For some, this is three to five degrees (Celsius) above normal."

And critically, the past two monsoon seasons have seen below average rainfall.

"This has had a huge impact on groundwater supplies," says Jacob.

Impact on the ground

The government estimates up to 330 million people could currently be affected by the dry climate conditions.

"We are seeing that people don't even have enough water for drinking," says Jacob.

Photos: India's drought crisis India was hit by the worst drought in decades in 2016. Here, gunmen stand alert at a water reservoir in Tikamgarh, India, on April 27. Hide Caption 1 of 14 Photos: India's drought crisis A gunman stands guard at a water reservoir in the central Indian state of Madhya Pradesh on Wednesday, April 27, 2016. Hide Caption 2 of 14 Photos: India's drought crisis A man walks on the dry reservoir bed next to Gunda Dam in India's western Gujarat state on Friday, April 1. Hide Caption 3 of 14 Photos: India's drought crisis A farmer poses in his dried-up cotton field in Nalgonda, India, on Monday, April 25. Hide Caption 4 of 14 Photos: India's drought crisis A farmer tries to revive his unconscious cattle in the Gondiya village on Thursday, April 21. Hide Caption 5 of 14 Photos: India's drought crisis A woman tries to filter water with her sari as a child drinks in the Shankargarh area on April 21. Hide Caption 6 of 14 Photos: India's drought crisis Cattle graze in a partially dried-up pond in central India on April 27. Hide Caption 7 of 14 Photos: India's drought crisis A farmer stands in his field in the village of Bangaye on April 27. Hide Caption 8 of 14 Photos: India's drought crisis Villagers fill drinking water from a leaking roadside pipe in Nalgonda on April 25. Hide Caption 9 of 14 Photos: India's drought crisis A villager walks with his cattle in the dried-up Mansaita River near Allahabad on Wednesday, May 4. Hide Caption 10 of 14 Photos: India's drought crisis A villager filters her water through a sieve in Shahapur. Hide Caption 11 of 14 Photos: India's drought crisis Villagers in Shahapur throw containers into a well on May 13. Hide Caption 12 of 14 Photos: India's drought crisis A villager transports water on his cart on May 13. Hide Caption 13 of 14 Photos: India's drought crisis Children run with containers toward a well in Shahapur, India, on May 13 2016. Hide Caption 14 of 14

In an open letter to India's Prime Minister Narendra Modi in April, more than 150 of India's activists and academics expressed their concern about the drought's impact on the rural population.

"In areas where rains have failed, farmers who depend mainly on rainwater to irrigate their crops have no, or very low, crop yields," they wrote.

"Those who rely on irrigation are also affected, with groundwater sinking and streams and reservoirs drying up."

The combination of heat with humidity makes India a global hot spot for heat-related illnesses and fatalities -- so far the government estimates more than 370 people have died.

2015's heatwave led to around 2,500 deaths in India , making it among the top five deadliest years in recorded history.

"It was a wake-up call for us," said K. Dhananjaya Reddy, the director of disaster management in Andhra Pradesh, a state that saw more than 1,300 deaths in 2015.

In 2016, as part of a prevention strategy, 10 cities across the hottest parts of India have teamed up with different organizations to create plans to combat the heat.

"All of the plans are focused on the most vulnerable population who don't have access to air conditioning, or have to work outdoors," says Anjali Jaiswal, Natural Resources Defense Council's India Initiative director.

The low-tech solutions range from warning systems, to medical training, to enforcing cuts to power and water supplies during cooler times. In Bihar, according to The Hindu , the increased threat of wildfires has even resulted in a cooking ban between 6 p.m. and 9 p.m.

Weird weather

El Niño is a periodic weather event characterized by warming ocean temperatures. The most serious effects are heat waves and water scarcity, and we are currently coming to the end of one of the worst El Niño periods in two decades.

While the effects of El Niño are global and widespread, it hits Asian countries the hardest : heat waves and drought become a more common occurrence, leading to energy, food and water insecurity.

JUST WATCHED El Niño causes global weather chaos Replay More Videos ... MUST WATCH El Niño causes global weather chaos 03:35

The good news is that this current El Nino system is fading , and the impending monsoon rains are offering rural villagers, as well as those locked into sweltering cities, some cause for optimism.

Meteorologists also say that the upcoming La Niña impacted monsoon is expected to be heavier than normal. "The forecast is quite positive," says CNN Meteorologist Pedram Javaheri.

At the start of the hottest month of the year, with forecast rains still weeks away, and no certainty that the coming rains will be enough, only time will tell how India will cope.