it can be the symptoms of aphid or sucking insects.

Check if there are aphid especially on the lower side of the leaves. Use Acetamiprid, Cypermethrin, Lambda-Cyhalothrin insecticides. Please don't use the single inscticide for a long time. Use alternatively.

you can also use this natural pesticide method. You can save money and save environment. https://youtube.com/shorts/hmEJtQdfbDY

may be mite problem so use abamectin insecticides.