What is the reason behind such damages on plaster surface?

[archdevil]

Can some one explain the reason behind such damages shown in the image along with rectification process?

 

[rames.psg]

I may be wrong

Anyway want to try

Peeling of plastered surface due to weather condition alternate wet and dry condition

Treatment would be prepare the surface with chicken mesh and apply rough plaster water proofing compound also can be applied then plaster the wall

Next step would be apply external putty and do primer and final coats

Please correct if I am wrong

 

[Khan Shaf]

Textural paint is also remedy for this

 

[AjitA]

Details about building not given.
May be due Plumbing issues if there is toilet at that location.
The defect in plumbing system and then suitable waterproofing can work

 

[sjudeprakash]

Also sand quality (fineness / too fine) can be another reason for these sort of patches, Also presence of salt in water / sand used for plastering can also be a reason for this failure