A Chinese airline is encouraging passengers to use toilets before boarding flights. The effort is to cut down on non-essential fuel use during flights.

The Chinese Southern Airlines estimates that a single flush at 30,000 feet consumes a litre of fuel, which is enough for an economical car to run at least 10 km, the state news agency Xinhua reported. Reducing human waste in the aeroplane's tanks would save 47 million yuan (around US $6 million) per year, the estimation notes. The airline also plans to improve its fuel-efficiency by carrying fewer non-essential items such as pillows and blankets, which accounts for a substantial amount of fuel use. Estimates show that an average aircraft uses 60 extra tonnes of fuel a day for blankets and pillows; if each seat is loaded with three 45-gm magazines, another 60 tonnes will be consumed. Apart from cutting expenses, the effort will also reduce carbon emissions, it says.

Fuel expenditure accounts for 35 to 40 per cent of the total operational costs of Chinese airlines.