‘A living lab’

The development’s orderly clusters of blocky, pale apartment buildings rise high above the villages outside its boundaries - a collection of shantytowns scattered along streets crowded with noxious traffic and roadside vendors hawking produce, meat, snacks and housewares.

Life for the tens of thousands of people living in those modern-looking towers is vastly different than for those living outside.

Inside the gates of Palava’s “Phase II” development - which one day could house more than 270,000 people - solar panels are a common sight. In addition to the city’s wind-cooling features, its buildings are designed to reduce how much heat seeps in.

Residents stroll through densely vegetated parks or down spacious, tree-lined sidewalks. Cars and buses trundle by quietly along wide roads - a stark contrast to the incessant honking heard on many of India’s gridlocked streets.

To reduce the need for cars, Palava’s architects designed the community to be a “5-10-15” city, an established approach for walkable urban areas. For residents, daily essentials are made to be available within a five-minute walk from their homes; things they need every several days are within a 10-minute walk; and what they may use within a week or month is no more than 20 minutes away.

“The 5-10-15 planning principle was actually one of the fundamental principles for planning the city,” said Sonal Bhide, the development’s lead architect. “You’re not using any transportation.”

Minakshi Kumari, who moved to Palava several years ago from the nearby city of Kalyan, walks every day.

The 37-year-old takes her two children to school on foot, sometimes allowing her 14-year-old daughter to walk alone. She routinely walks to the grocery store or outside the gate to buy produce from roadside vendors. In the evenings, she and her husband amble through the park nestled in the middle of their apartment complex.

“There was no proper place to walk [in Kalyan],” Kumari said, adding that in Palava, “the air is refreshing. There’s no pollution, no honking from too many vehicles in the street.”

Like many residents in Palava’s high-rises, Kumari rarely turns on the four air conditioning units in her three-bedroom apartment. She prefers to leave her windows and balcony door open to let in the breeze.

Keeping buildings cool with minimal energy is a priority for Palava’s developers, who have continued to try different strategies since construction began.

Early apartments were built with smaller windows to reduce the amount of heat that could enter, Abdullah said. But when residents complained about the window size, he said, the developers responded by constructing apartments with larger windows set farther back into the building. This design provides shade and cuts the amount of direct heat hitting the glass. More recently, Abdullah said, they’ve been experimenting with glass treatments such as films that can be applied to windows to keep heat out.

On a sunny June day, the interior of a newly constructed unit with treated windows is noticeably cooler than the outdoors, even with the air conditioning shut off.

But window design is just one way the community saves energy. Palava has cut residential energy use through a combination of approaches, including installing solar-powered water heaters on buildings and efficient air conditioners inside.

Around 30,000 five-star ACs - rated as the most efficient - are installed in the city’s Phase II development. Some empty units are serving as testing sites for next-generation air conditioners that could slash energy use and emissions even further.

If residents allow it, the developers hope to install sensors that will provide more insights into energy use and ways to make improvements.

“Without data … we can only speculate,” Abdullah said.

The city is also engineered to cope with extreme weather.

Many of the development’s public green spaces are situated to buffer against floodwaters. One major park features a bioswale, a grassy channel that helps control stormwater’s velocity to prevent flooding. Rainwater is collected and stored in two quarries in case of shortages.

The community also has its own wastewater plants, and is able to treat and reuse all of its graywater - what drains from showers, tubs and sinks, as well as from washing machines - and blackwater, which comes from toilets.