(e) Propane and Butane. These fuels are in great demand for industry and for domestic purposes in rural areas. In addition to the above, naptha and methane are used to a small extent. 4. If the best use is to be made of alternative fuels in road transport, the rationing system will have to take into account such factors as the quantities available, the distance from source of supply and the efficiency of the method of use. 5. I accordingly seek the approval of the Committee to the following principles:(a) From such date as may be decided on no vehicles shall be allowed to operate for purposes which would not justify an allowance of petrol and diesel oil, whatever the fuel used.