Domestic stocks fell for a second day after official data showed manufacturing contracted for a third month and the authorities detained a top-performing hedge-fund manager in widening probes into market manipulation and insider trading.

The Shanghai Composite Index dropped 1.7 percent to 3,325.08 points at the close, while the Hang Seng China Enterprises Index slid 1.5 percent in a fifth day of losses, the longest losing streak in almost two months. PetroChina Co and Aluminum Corp of China Ltd led declines for commodity shares, sliding at least 2.5 percent.

Police raided hedge fund Zexi Investment on Sunday, according to a source familiar with the matter. The 26 companies of which Zexi disclosed as a shareholder in the past 12 months fell by an average of 4.5 percent on Monday.

The two-day retreat for the Shanghai index has pared a rebound to 14 percent from this year's low on Aug 26 as the government took measures to stabilize the stock market and policymakers introduced more measures to boost growth amid the slowest economic expansion in a quarter of a century.

"There has been no fundamental improvement to drive equities higher," said Michael Every, head of financial markets research at Rabobank Group in Hong Kong. The CSI 300 Index declined 1.6 percent. Hong Kong's Hang Seng Index lost 1.2 percent. Trading volumes in Shanghai and Hong Kong were at least 9 percent below the 30-day average.

Gauges of energy, material and telecom shares in the CSI 300 dropped more than 2 percent for the worst performances among 10 industry groups. Yanzhou Coal Mining Co slid 2.5 percent, while China Shenhua Energy Co, the biggest producer of the fuel, lost 2.1 percent. Chalco slid 3.1 percent. Tongling Nonferrous Metals Group Co, the nation's second-largest copper smelter, plunged 6.4 percent.

China's factory gauges signaled that manufacturing still has not bottomed out amid faltering global demand and deepening deflationary pressures.

The official Purchasing Managers Index was unchanged at 49.8 in October, the National Bureau of Statistics said on Sunday. That compared with a median estimate of 50, the line between expansion and contraction, in a Bloomberg survey of economists. The official non-manufacturing Purchasing Managers' Index, a barometer of services and construction, fell to 53.1 from 53.4 in September, the weakest since December 2008. A separate PMI from Caixin Media and Markit Economics was 48.3 in October.

China needs to have an average economic growth of above 6.5 percent in the next five years to meet the goal of achieving a "moderately prosperous" society by 2020, Premier Li Keqiang said in a speech in Seoul on Sunday, according to a government statement.

In Hong Kong, Air China Ltd slid 4.7 percent after the carrier posted a 13 percent drop in third-quarter net income. New China Life Insurance Co fell 2.6 percent after the insurer reported a 27 percent drop in net income in the third quarter. Around 69 percent of H-share companies that reported third-quarter results have trailed analysts' forecasts, versus 55 percent for the MSCI Emerging Markets Index.

Chinese police detained officials from two brokerages for illegal trading of equity-index futures, Xinhua reported on Sunday, in the latest attempt to crack down on moves blamed by the authorities for exacerbating a recent stock market rout.

"For the short term, it's quite negative on small-cap stocks as it will dampen investment sentiment on the sector and lots of Zexi's major stock holdings need to be closed," said Li Jingyuan, head of securities investment at Shanghai Zhaoyi Asset Management.