oil futures slumped early wednesday after weak economic data out of china underlined worries about demand from one of the world’s largest crude importers   west texas intermediate crude for july delivery cl00 cl1 cln23 fell 203 or 29 to 6743 a barrel on the new york mercantile exchange   july brent crude brnn23 the global benchmark was down 194 or 26 at 7160 a barrel on ice futures europe august brent brn00 brnq23 the most actively traded contract dropped 186 or 25 7185 a barrel   back on nymex june gasoline rbm23 was down 17 at 2552 a gallon while june heating oil hom23 dropped 13 to 2251 a gallon   july natural gas ngn23 was off 06 at 2314 per million british thermal units china’s official manufacturing purchasing managers index fell to 488 in may from 492 in april the national bureau of statistics said wednesday the result was also below the 497 expected by economists surveyed by the wall street journal it marked the second month in a row that the reading fell below the 50 mark which separates activity expansion from contraction “investors are nervous about future demand a feeling exacerbated by disappointing chinese manufacturing data released overnight with the economic outlook remaining uncertain for the world’s largest crude oil importer demand expectations are falling causing prices to drop” ricardo evangelista senior analyst at activtrades said in a note oil ended at nearly fourweek lows on tuesday pressured by worries over economic growth a june 4 meeting of opec the organization of the petroleum exporting countries and its allies including russia is in focus saudi arabia’s energy minister earlier this month warned that short sellers should “watch out” remarks that were viewed by analysts as a warning that a further round of production cuts could be in the offing but russia’s deputy prime minister subsequently said he saw no need for additional measures “i tend to think that opec will leave production unchanged unless the brent curve is trading in contango at the close on friday” robert yawger executive director of energy futures at mizuho securities said in a note in contango laterdated futures trade at a higher price than nearby futures “contango greater than cost of carry which kicks in at 50 cents to a dollar is worst case scenario for all producers and opec would likely do their best to nip deep contango in the bud before it can grow” he wrote august brent was trading at a premium of around 15 cents to july early wednesday