(May 18): Vietnam’s largest city is rolling out measures to conserve power as a spell of extremely hot and dry weather highlights the risks of the country’s heavy reliance on hydropower.

Ho Chi Minh City has asked factories, malls and schools to turn off half of their elevators and hallway lights, according to reports that cited the local government. It’s also cutting down on street lighting and urging people to wear less-stuffy clothing.

The conservation efforts followed a call this week from Vietnam Electricity Group for municipal authorities to cut usage by 5% to 10%. The state-owned utility warned that many of the country’s major reservoirs were near 100-year lows. Around a third of the nation’s electricity comes from hydro, making it vulnerable to droughts, according to the latest available set of annual figures.

Parts of Asia have been hit by sizzling temperatures over the last few weeks due to an emerging El Nino weather pattern, which typically brings hotter and drier weather to the continent. Many countries are still grappling with the fallout from last year’s spike in energy prices, making them more susceptible to surges in demand.

Temperatures jumped to record high levels in Vietnam and Laos earlier this month, while some Chinese cities are bracing for another round of power shortages this summer due to the heat.

El Nino is forecast to develop in the coming months, which typically increases global temperatures in the year after it develops. That’s an ominous sign for the northern hemisphere as it moves into summer.