(Updates with closing prices) Sept 20 (Reuters) - Hong Kong shares closed at their lowest level in 11 months and the offshore yuan and Hong Kong dollar weakened on Monday, as a plunge in beleaguered property developer China Evergrande Group led other stocks in the sector lower. The benchmark Hang Seng Index closed down 3.34%, its worst percentage decline in nearly two months, and its lowest close since late-October, dragged down by the property sector. The blue-chip developer index lost 6.7% and a broad index tracking property and construction stocks fell 6%. Mainland Chinese stock markets are closed for the mid-autumn festival, although FTSE China futures traded in Singapore shed 3.22%. “Market sentiment is fragile in Hong Kong at the moment,” said Dickie Wong, research director at Kingston Securities. He said the declines were due to growing risks of defaults at Chinese property developers and concerns that Beijing’s “common prosperity” agenda would also include Hong Kong real estate names, though he said the latter was likely an overreaction. Beijing has told Hong Kong’s powerful property tycoons to do more to help solve the financial hub’s potentially destabilising housing shortage, Reuters reported last week. Evergrande was once again one of the largest decliners, closing down 10.2% having dropped as much as 19% at one point to a fresh 11-year low. The stock has fallen more than 85% so far this year. The developer has been scrambling to raise funds to pay its many lenders, suppliers and investors, with regulators warning that its $305 billion of liabilities could spark broader risks to the country’s financial system if not stabilised. The company is due to pay $83.5 million interest on Thursday for its March 2022 bond. Evergrande’s woes also hurt bank stocks. Reuters reported last week that Agricultural Bank of China, had made some loan loss provisions for part of its exposure to Evergrande, while China Minsheng Banking Corp and China CITIC Bank Corp Ltd were considering rolling over some of their near-term debt obligations, citing sources with knowledge of the matter. Ag Bank’s Hong Kong shares finished down 3.3%, Minsheng Bank’s lost 5.9% and CITIC Bank’s shed 5.1%. The fallout also added to pressure to the yuan, which fell to a three-week low of 6.4848 per dollar in offshore trade . “I think it’s one of the triggering points,” said Mizuho analyst Ken Cheung, who said market instability generated by Evergrande added to the dollar’s allure along with recent weak economic data in China and expectations of U.S. tapering. “With onshore markets on holidays, the PBOC may have less guidance over the renminbi,” he added. The Hong Kong dollar dropped to 7.7881 a dollar, also its lowest level in three weeks. (Reporting by Alun John, additional reporting by Tom Westbrook; Editing by Sam Holmes and Uttaresh.V)