Why are there spots of corrosion/rust on a newly painted surface

Spots of corrosion on the surface of the newly painted surface due to industrial fall outs.

What are the possible causes?

• Iron particles which falls on top of the surface which oxide the attack the paint film.
• Industrial fallout which damages the paint film can cause the corrosion spots.
• Spark damages due to welding or grinding operations..

How can I fix the problem?

• Immediate removal of metal particles.
• During welding or grinding work ensure that the painted area covered & protected..