The film was shot for 28 days on the streets of Mumbai. Except a shot in an airport washroom, everything was shot outdoors in some of the most congested areas of Mumbai. The makers first tried shooting with normal cameras, but that didn't work. Coming from television, Rajeev Khandelwal was immediately recognized by people in Dharavi and Dongri when the saw cameras pointing at him.
The film was believed to be a remake of the Filipino film Cavite (2005). Writer-director Raj Kumar Gupta clarified he hadn't seen Cavite before making Aamir; he prepared the script before Cavite was released, and thus contacted the makers of Cavite to clarify about the same. The director duo of Neill Dela Llana and Ian Gamazon, who directed Cavite, explained they had no objection to it and revealed how Cavite itself was alleged to be inspired by Phone Booth (2002) and Cellular (2004). Humbled by their gesture, the makers of Aamir thanked the duo in the film's prelude.
Whenever Rajeev Khandelwal can be seen talking into the phone, it's actually the director Raj Kumar Gupta instructing him rather than the people in the plot.
While shooting on the road in Dongri where Rajeev Khandelwal had to run across the street and there couldn't be a retake for obvious reasons, he was spotted by a woman from a taxi. She stopped her vehicle mid-street got out and started screaming his name. The camera was rolling. He told her he needed to cross the street before the lights changed from red to green. She didn't listen, so he gently pushed her hands away and crossed as per script. That shot of the woman stopping him is in the film.