a part of cause of action arises within its territory, and the cause of action arises in the present case on account of challenge to the impugned letters dated 6.7.2015 and 30.7.2015. These letters however achieve finality by their communication, and which communication is admittedly done to the petitioner not at Delhi but at Dadri, UP vide Sethi Auto Service Station and Another Vs. Delhi Development Authority and Others, 2009 (1) SCC 180 . The entire cause of action therefore with respect to challenge to the impugned letters dated 6.7.2015 and 30.7.2015 arises outside Delhi, and at Dadri, UP and therefore, this Court does not have territorial jurisdiction. Once this Court does not have territorial jurisdiction because neither whole nor a part of the cause of action has not arisen in Delhi, accordingly, the writ petition has to be and accordingly liable to be dismissed for lacking territorial jurisdiction.