Who regulates and implements CCTV usage?

Who draws the line at what is public interest and just plain harassment when a camera is placed. What about the private camera placed on property with malicious intent? Who regulates the camera on private property? Yes surveillance cameras are important to deter crimes, however it is important to note who is at the other end of the camera? Who really is watching you? Who ultimately views what the camera lens observes? Who decides when a privately owned security surveillance camera is poorly or maliciously aimed (when the camera is deliberately pointed into the windows of a private residence)?

Back in 2014, Delhi Metro CCTV footages were on YouTube and also at some questionable sites. Who owns responsibility for not misusing the data of public CCTV surveillance? In short – who decides and regulates?