Shanghai - Amidst the skyscrapers of a modern Chinese metropolis, the city's oldest neighbourhood shivers through the winter thanks to an old rule forbidding central heating.
In Laoximen, not far from Shanghai's swanky riverfront Bund, locals and migrant workers bundle up in thick coats inside houses built decades ago.
To save energy, the Chinese government decided in the 1950s that areas of the country south of the Qinling mountains and Huaihe river in north-central China would not have state-provided central heating.
Shanghai lies in the designated southern zone even though average temperatures in winter are around four degrees at night and 12 degrees during the day.
And in the city's lower-income neighbourhoods such as Laoximen, people are too poor to pay for electric heaters.
Many of them own air conditioners that can double as heating devices, but they are left largely unused in the winters because residents cannot afford the resulting electricity bills, which can top 100 yuan per month ($15) or much more.
The area used to be the city's cultural centre. Surrounding a Confucian temple, the mostly two- and three-storey wooden buildings remain at the heart of Shanghai's commercial district even today.
It is in this neighbourhood that migrant workers can rent homes for just 1,000 yuan ($150) a month.
For Zhang Dongjun, a 57-year-old street sweeper, a heater was too much of a luxury to pack into his tiny single room: a bunk bed takes up most of the space. He uses an electric blanket to keep himself warm at night.
A woman in her 70s who gave only her surname, Yin, complained about the lack of a more affordable heating system.
The cold weather makes her legs ache, Yin said, adding she spends most of her retirement money on healthcare costs.
"Heaters use electricity and we never turn them on unless we have friends or family visiting us," she said.
"Most of the time, we just use a hot-water pouch to keep our hands warm." Bao Shanchun, who collects antiques from the many old houses being demolished around Shanghai, shares a heater with another man in a space less than 10 square meters. But it is not turned on even at night.
"I'm very happy here to earn one or two hundred yuan a day. To make money every day makes me happy," said Bao, who came to Shanghai 15 years ago from nearby Jiangsu province because he thought "gold is everywhere" in the city.
"I will go back to my hometown when I'm 70," said Bao, now 64.
"I have big houses there."