Thanks for posting your query.
Pleural thickening most commonly occurs as sequelae of Pulmonary Tuberculosis
. More so in India and that is why you were declared unfit for work.
You need to be treated for it, if Tuberculosis is confirmed. Please get back to your primary care
physician and get this confirmed and treated accordingly. Once your treatment is complete, you can try again for the job in gulf.
All the best to you.