Mainland-related shares dived yesterday amid renewed fears that the yuan might be devalued and expectations that the severe flooding in China would slow growth, brokers said. The H-share index fell 6.34 per cent to 267.34 points, while the red-chip index dropped 5.14 per cent 583.93 points, compared with the 0.19 per cent fall in the Hang Seng Index, where stocks were buoyed by government intervention. Brokers said Russia's devaluation of the rouble on Monday gave markets another reason to fear the mainland might succumb to pressures for a devaluation. The floods have hit China's northern industrial belt, where some H-share firms are based. 'The flooding in the heavy industry towns of northeast China is scaring investors off H shares,' a broker said. H shares have lost 35.1 per cent since July 17, while red chips have shed 29.6 per cent.