China's powerful state planner said on Thursday it had not considered reducing the tax on vehicle purchases, seemingly pouring cold water on industry hopes that Beijing might cut the tax by half to shore up the flagging auto market.  Meng Wei, spokeswoman for the National Development and Reform Commission, said the world's largest auto market was under pressure but that the slowdown could actually help weed out weaker players.  "Objectively, this (slowdown) could help stimulate the workings of the market, strengthen the industry's core competitiveness and eradicate outmoded capacity," Wei told a press conference in Beijing.  "Currently our commission has not considered or proposed the idea of 'cutting the purchase tax to 5 percent'," she added. The purchase tax rate is currently 10 percent.  China's car market is on the brink of an annual contraction not seen since at least 1990 after sales fell 11.7 percent in October, the fourth straight month of declines.