After shooting most of the clip it seems that the colour must really be changed to add an overall drab tone by washing out most of the colour similar to the picture on the left taken from Danny Boyle's "28 Days Later' which was shot with a fairly average budget of £5 million, which then earnt almost £40 million when it became a surprise hit in the US which continued to earn many awards and give Danny Boyle such a high status.
The desolate streets that appear in the film gave me the idea to film in a deserted area as the shot alone of an empty place is quite haunting......