Pharmaceutical doors

Why pharmaceutical doors are blue/silver colour and walls are in white colour, any reason is there

It is not regulatory requirement but dust can be easily seen on this colour if they are colour also signifies inspiration.

No such reason. White walls are essential to easily see if dust is attached on walls, so we can make visual check of cleaning. Doors are made of similar colours as they are manufactured in large quantities by aluminium section manufacturers. But, doors should also be essentially of a colour where cleanliness of the area can be observed easily.