(a) the society shall establish and maintain a fund of not less than twenty- five thousand rupees for the first fifty vehicles or fractional part thereof and pro rata for every additional vehicle in the possession of 1[ members of, and insured with, the society subject to a maximum of one hundred and fifty thousand rupees] and the said fund shall be lodged in such custody as the State Government may prescribe and shall not be available for meeting claims or other expenses except in the event of the winding up of the society;