Section 93(6)(ii) in The Central Motor Vehicles Rules, 1989
(ii)'axle-lift device' means a device permanently fitted to a vehicle for the purpose of reducing or increasing the load on the axle(s), according to the loading conditions of the vehicle, either by raising the wheels clear off the ground or lowering them to the ground or without raising the wheels off the ground (e.g., in the case of air suspension systems, or other systems), in order to reduce the wear on the tyres when the vehicle is not fully laden, or make starting (moving off) on slippery ground easier for motor vehicles or vehicle combinations, by increasing the lead on the driving axle.];