A.C. Drain pipe work for convenience of neighbour

Respected Sir/Madam, Jai Hind !!! Jai Bharat I have three side open home. The fourth side having my home wall besides to my neighbour. My drain pipe of A.C. is concealed which was going to my neighbour. Neighbour has blocked my drain as drain water was going to his compound.I want to conceal this drain pipe towards my garden so that drain water should not go to his side. Neighbour has not allowed the person to do the work. Work shall be performed by labour from his side. I said to that labour will finish his work and clean the waster. But when I was not available my neighbor has threatened labour and he disappears because they asked to have possession of labour material & do the police case if labour continues to work. Labours are doing work and if neighbour will capture his tools & tackles then labour has to suffer for his daily breads. He also threatened labour for closing my chimney opening & window opening which was opened on his side. I don't know the rules so please guide me.