BEIJING- To go inside, Madam Quan Youzhi, 66, had to lift a lid weighing at least 10kg and descend 3m underground.
Her home was an underground shaft in Beijing's Chaoyang district.
It measured 3m by 3m and was about 2m high, China Daily reported.
Inside her home were simple furnishings: a few quilts on a thin mat, some candles, two coats and a broken umbrella.
Madam Quan is from Shangqiu, Henan province, and makes about 20 yuan (S$4) a day selling bottles.
"Twenty years," she said when asked the obvious question of how long she had been living underground.
"I don't have money," she said.
Madam Quan added that city officials frequently blocked off access to her home by welding the lid shut.
She said: "I bought a metal saw and used it to open the lid after they left."
She was once taken to a rescue centre, but left after a few days.
Her husband, Liu Wancang, 68, lived in a similar compartment nearby.
On Friday, local authorities blocked the underground compartments with cement.
Mr Ge Daoshun, a researcher of social policy at the Chinese Academy of Social Sciences, said it was right for the government to block them off because of the potential safety hazard.
But homeless people such as Madam Quan will find a similar place to live, he said.
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