基础建设板块9月18日跌1.51%，农尚环境领跌，主力资金净流出6.46亿元

Group 1 - The infrastructure sector experienced a decline of 1.51% on September 18, with the Shanghai Composite Index closing at 3831.66, down 1.15%, and the Shenzhen Component Index at 13075.66, down 1.06% [1] - Notable stocks in the infrastructure sector included Dongzhu Ecology, which rose by 10.03% to a closing price of 10.42, and Hongrun Construction, which increased by 10.02% to 11.31 [1] - The trading volume for Dongzhu Ecology was 955,800 shares, while Hongrun Construction had a volume of 734,200 shares [1] Group 2 - The infrastructure sector saw a net outflow of 646 million yuan from institutional funds, while retail investors contributed a net inflow of 544 million yuan [3] - Speculative funds recorded a net inflow of 102 million yuan into the infrastructure sector [3]