Chinese customs authorities are offering rewards for valid tip-offs in a crackdown on domestic and foreign companies involved in customs fraud, the Financial Times said. Tariff income in the first seven months of this year was 3.9 per cent lower than in the same period last year, giving rise to fears that customs fraud is on the increase. The authorities are particularly concerned with valuation fraud in which high-duty goods are wrongly reported as low-duty ones. In the first half of this year, 272 such cases, involving evaded duties worth Yn380m, were uncovered. Most of the cases involved domestic firms.