Entrepreneur Tony Verb is on a mission to promote technology that can help make cities greener and smarter in China's Greater Bay Area, now being shaped as a low-carbon megalopolis.
Hong Kong-based Verb, co-founder of investment firm GreaterBay Ventures & Advisors, plans to back urban tech businesses working on autonomous e-vehicles, flying taxis, artificial intelligence, robotics and clean energy.
Verb is betting on China's master plan to develop the Pearl River Delta into a sustainable innovation hub, which he believes will serve as "a great case study" for the world's cities.
In February, Beijing announced it would foster links between nine cities in Guangdong and the special administrative regions of Hong Kong and Macau to forge the world's biggest urban area with 70 million people.
Under the Greater Bay Area (GBA) plan, each city has a different role, but the blueprint is centred on developing the delta in a high-tech way that also conserves its ecology.
The strategy comes as China exits an era of breakneck growth when planning and finance for infrastructure were overlooked, Witman Hung, Hong Kong deputy to China's 13th National People's Congress, told the Thomson Reuters Foundation.
Travel Sentry founder John Vermilye remembered visiting factories in the delta in 2003, and seeing plastic pellets flowing into sewage drains and workers in flip-flops carrying pots of molten zinc from the furnace to moulding machines.
"Sixteen years ago, we were telling businesses how to be sustainable and what changes they needed to make - but now they're getting this from the government directly," said Vermilye, whose firm develops luggage security standards.
Marred by smog, dirty soil and contaminated water, China - the world's biggest energy user and greenhouse gas emitter - decided development had to respect and protect its environment.
Leaders introduced "ecological civilisation" as a constitutional goal in 2012, said Christine Loh, chief development strategist at The Hong Kong University of Science and Technology (HKUST).
In 2014, Beijing declared war on pollution, introducing environmental laws and inspectors who swept through businesses.
It then launched "Made in China 2025", cementing a move away from the world's factory floor to innovation-led growth.
While Hongkongers may be divided about closer political and legal ties with the mainland, the GBA is already an economic powerhouse attracting many startups.
Its GDP is $1.6 trillion, similar to Tokyo Bay, and leaders want it to rival Silicon Valley.
Shenzhen is home to tech heavyweights like Tencent and Huawei. It is also one of China's three sustainable development zones, tasked with serving as a technology testbed for green solutions in sectors like waste and environmental restoration.
The coastal megacity of 12.5 million helps the bay lead the way in electric vehicles and low-carbon transit.
"All over the delta, you are seeing the gradual rollout of e-buses, e-vans and e-taxis," said Loh.
That came after Beijing started giving subsidies for electric transport, buoying home-grown e-vehicle maker BYD.
Shenzhen now has 16,000 e-buses plying its streets, a world first, and by the end of 2018, it also had 20,000 e-taxis, Xinhua reported.
Meanwhile, electric trains whizz around the delta. Hong Kong's MTR alone moves 5.76 million passengers each weekday in a city of 7.4 million. This year authorities linked up Hong Kong to the mainland's express rail link, slashing commuting times.
With Beijing's target to cut energy consumed per GDP unit by 3% this year, bay officials are also pushing green construction and the use of data and technology, deputy Hung said.
"Every time there's a new building, every time a power plant is being built or modified, you have to meet such rules," he added.
Siu Hung Chan, managing director of power company CLP's China business, said data analytics and machine-learning are fostering smart cities in the delta.
Shenzhen uses street cameras and apps to direct drivers to carparks and uncongested roads, while Cisco is building a "model smart city" in Guangzhou's Panyu district.
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Still, the bay's history as the world's workshop and site of three of its ten busiest ports means the challenge is big.
"While the industries are gone, the rivers are still there and the pollution is still there," said Hung.
The GBA sits in the Indo-Burma hotspot, one of the world's most biodiverse areas, but also one of its most threatened. When Shenzhen's mayor took office in 2017, his first priority was taking care of the black, smelly water, Hung said.
Now there is a "river chief system", led by the mayor who is personally in charge of several rivers, while almost 100 officials have been assigned to look after others.
"It becomes their personal responsibility to make sure the river becomes clean again," said Hung.
With the delta spanning three administrative areas, there have been cross-border efforts to clean up the air, but it often falls short of World Health Organization standards.
Another part of the GBA plan is to protect wetlands, forests, coastlines and marine ecosystems.
A group of Hongkongers, led by local foundation AquaMeridian and the Canadian International School, have nominated the city's southern waters to be protected under a conservation campaign run by non-profit Mission Blue.
As the planet warms, many studies deem the region at high risk of floods and landslides, but there are also opportunities to plan better for those threats, said Loh of HKUST.
With the population seen growing to 100 million by 2030, according to Savills, the delta is testing "sponge cities" where landscapes and underground tanks absorb and store rainwater.
Weather chiefs from the three administrations are also exploring how AI and data can improve forecasts, while AI is being used to predict landslides.
HKUST, meanwhile, uses drones to sniff emissions from ships to see if they have switched to cleaner fuel.
Loh is hopeful of a greener future for the GBA, noting the low-carbon development plan enjoys top-level political support, with Hong Kong playing a key role in financing green projects.
"China is speed-fighting pollution," she said.