Citrus leaf miner. You can find a lot of info on YouTube on how to protect your trees.

CLM. Not a disease, an insect pest.

Like they said CLM, mature trees usually tolerate it ok without need for treatment, just ugly leaves, typically it does not hit outdoor trees until mid summer.

If the OP is in a tropical / subtropical country CLM can be around all year round.

Dear All, many thanks for your valuable feedback. I will try to read more about CLM to find a solution to this problem.