What happened 1975 AD in China

Typhoon Nina, known in the Philippines as Typhoon Bebeng, was the fourth-deadliest tropical cyclone on record. At least 229,000 people died after the Banqiao Dam (in Zhumadian, Henan Province, China) collapsed and devastated areas downstream. The collapse of the dam due to heavy floods also caused a string of smaller dams to collapse, adding more damage caused by the typhoon.