Section 94(3)(iv) in The Central Motor Vehicles Rules, 1989
(iv)[ the Non-Skid Depth (NSD), shall not be less than 0.8 mm in the case of two-wheeler and three-wheeler and 1.6 mm in the case of other motor vehicles, below the Tread Wear Indicator (TWI) embedded in tyres at the time of manufacture:] [Inserted by GSR 221(E), dated 28.3.2001 (w.e.f. 28.9.2001).]