Foxconn reported that sales for its smart consumer electronics division, which includes smartphones, fell year on year in November, owing in part to production interruptions in Zhengzhou. Foxconn manufactures around 70% of iPhones.

The Zhengzhou facility has been dealing with rigorous COVID-19 limitations, which have fuelled worker dissatisfaction with manufacturing conditions. Production of the Apple gadget was halted ahead of the Christmas and Lunar New Year holidays, with many staff either being forced to isolate to prevent the virus from spreading or abandoning the company. Following the November outbreak, which saw employees struggle with security forces, Foxconn may have lost more than 30% of its November output at the Zhengzhou factory. 

Movement of Apple in the last five years. (Source: Trading Economics)

Sources:

https://tradingeconomics.com/aapl:us

https://flipboard.com/article/foxconn-expects-covid-hit-china-plant-back-to-full-output-in-late-december-or-ea/f-611fd5aa55%2Frappler.com

https://www.forexlive.com/news/forexlive-asia-pacific-fx-news-wrap-chinese-stocks-higher-usd-lower-20221205/

https://www.asiafinancial.com/covid-concerns-add-to-apples-need-to-diversify-out-of-china

https://www.investing.com/news/stock-market-news/foxconn-expects-full-production-at-covidhitchina-plantlate-december-to-early-januarysource-2956992