Need handrail for drop off of 600mm?
There are building code requirements for a porch: In the USA, if your porch floor is less than 30 inches high from the ground, a porch railing is NOT required by code. In Canada the maximum height from the ground is 24 inches.Sep 20, 2014. 

Other parts of the world may have different codes or none at all.  So your question will have different answers depending on your location. 

Since you live in Qatar I would use international building code which states the following 


  On a stair, since handrail must be between 34" and 38", the handrail and the top of the guard can be one and the same. In commercial applications, the IBC requires a minimum height of 42". On stairs, once there is a 30" drop, a handrail will be required and placed between 34" and 38" above the nosing.


Short answer is that unless Qatar has codes that vary from international standard you don’t need a handrail for 600mm (23.62”)