For years, Cai Jinlian in Hebei province envied her sister, Cai Jinrong, who lived a much better life than her, just 1 kilometer away in Beijing.

The two sisters grew up in the mountain village of Lishuigou in Hebei, but Cai Jinrong married a farmer about 30 years ago and moved to a village that is within walking distance of Lishuigou but administered by Beijing. She enjoys clean tap water and lives in a two-story villa.

However, Cai Jinlian, who never leaves Lishuigou, was still drinking well water two years ago and she had to pay long-distance call charges to talk with her sister. The road to her rundown bungalow is badly potholed.