Asian share markets outside mainland China tumbled on 24 July as a private gauge of Chinese manufacturing unexpectedly hit a 15-month low.
The preliminary Purchasing Managers' Index (PMI) from Caixin and Markit Economics came in at 48.2 in July compared to 49.4 in June - well short of analyst expectations for a score of 49.7.
A score above 50 indicates expansion while one below signals contraction.
The data revived investor concerns over China's economic outlook, with Hong Kong's benchmark Hang Seng index slipping 0.9% to 25,161.26 points during mid-day trading.
Seoul's KOSPI dipped 0.8% to 2,047.54 and Australia's S&P/ASX 200 benchmark was down 0.5% at 5,562.50 points.
Shares in mainland China bucked the regional trend, however, with the Shanghai Composite index rising 1% to 4,167.93.
Meanwhile, Tokyo's Nikkei benchmark fell 0.6% to 20,554.83 despite PMI data showing Japan's manufacturing sector expanded at a faster pace in July.
The Nikkei-Markit PMI hit a five-month high of 51.4, a marked improvement from the 50.1 reading recorded in June.
"Production rose at the quickest rate since February, while new order growth was the second-strongest this year so far," said Markit economist Amy Brownbill.
"Subsequently, employment rose at the fastest rate since December 2014 and buying activity growth resumed."
Ayako Sera, senior market economist at Sumitomo Mitsui Trust Bank, told Reuters: "Japan's PMI was good, but Japanese stocks are reacting more to China's.
"Everyone is concerned about the state of China's economy, and this reaction shows that market is very sensitive to information like this."
Elsewhere in the region, New Zealand posted a trade deficit of NZ$60m (£25.5m, €36m, $39.5m) in June, compared to a NZ$371m surplus in May.