The gap between ethylene supply and demand stands at 3.3 million tonnes last year, creating a mainland shortage despite the fact the country is stepping up efforts to increase production, according to yesterday's China Petrochemical News. It said the country produced 4.3 million tonnes of ethylene last year. However, annual demand reached 7.78 million tonnes, leaving a gap of 3.3 million tonnes. This year it expects to produce 5.05 million tonnes.