Q.Kaffir Lime Tree Problem
I plant this tree 10 year ago.. recently I notice something not right. Need your advise base on the photo I sent you..

Certified GKH Gardening Expert
This is unfortunate. It looks a lot like citrus greening, caused by Candidatus Liberibacter asiaticus. There is no known cure or treatment for Candidatus Liberibacter asiaticus, also known as citrus greening disease, which affects citrus plants. This bacterial infection is transmitted by the Asian citrus psyllid and can lead to the decline and death of infected trees. The only effective management strategy is to prevent the spread of the disease through early detection, monitoring, and the use of insecticides to control the psyllid population. Additionally, planting disease-resistant citrus varieties and practicing proper cultural care can help minimize the impact of citrus greening disease.
I would contact your local extension service to confirm or make another diagnosis.
https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm