Customs duty cut from 7.5% to 2.5%. THE FINANCE minister has announced that Customs duty on bio-diesel will be reduced from 7.5 per cent to 2.5 per cent and duty-paid high-speed diesel blended with up to 20 per cent bio-diesel will be fully exempted from excise duties. This, say industry experts, is a strategic move which will boost use of bio-diesel, considering the fact that diesel accounts for around 40 per cent of fuel consumption in the country.