As per IS : 875, for the purposes of specifying basic wind velocity, the country has been divided into A. 4 zones B. 5 zones C. 6 zones D. 7 zones

The correct answer is:

A. 4 zones

As per IS : 875, for the purposes of specifying basic wind velocity, the country has been divided into 4 zones.

The zones are:

• Zone I: Plains
• Zone II: Hills
• Zone III: High Hills
• Zone IV: Very High Hills

The basic wind velocity is the mean hourly wind velocity at 10 m above the ground. It is used in the design of structures to resist wind loads.

The basic wind velocity is determined by the following factors:

• The geographical location of the structure
• The height of the structure
• The type of structure
• The occupancy of the structure

The basic wind velocity is specified in IS : 875. The values of the basic wind velocity for different zones are given in the following table:

Zone | Basic wind velocity (km/h)
——- | ——–
I | 30
II | 35
III | 40
IV | 45