One of the reasons stated for last summer's crazy jump in oil prices was the increasing global demand, especially from China and India. Now a group of green scientists are calling on the Indian government to impose taxes on cars to stem energy use. The Centre for Science and Environment said the government must address the "linkage between vehicles and energy insecurity." A report from the group says private vehicles account for 62 percent of diesel consumption in the transport sector. The group says India must introduce fuel economy standards and must also reverse a trend of lowering taxes on vehicles. Officials say more consumers have disposable income and are purchasing larger vehicles. The share of cars with 800cc engines has dropped from 21 percent in 2001 to just 11 percent in 2004 while the share of mid-size and large vehicles is growing. With this shift, fuel consumption and emissions are rising. Another key point in the report is that while India is promoting diesel vehicles for fuel efficiency, these models pollute much more.