No such requirements in mentioned in EHS acts and rules. practically it is not possible !
For high hazard industries, Large no of tanks with tonns of capacity installed in kilometers. oil & gas companies spread in 100 to 1000 acres. In such plants Hazardous area spread around atleast 1km to 10km area.
for small to medium scale Industries plant spread in 5 to 50 acres. If govt precribes any fixed distance, it will not give effective results.
In practical assembly points are created at four ends of plant. based on the wind direction , during emergency employees will evacuate from safe gates.