Pollution
The central theme of the novel is that of pollution, chiefly, its dangers. The book positions pollution as an enemy, and the book begins with the arrival of a large, threatening black cloud that looks as though it will engulf London. It is also shown to be something that both London and UnLondon need to be rescued from.
The novel references the Clean Air Act of 1956, which was instituted by the Royal Meteorological Society and which tried to reverse some of the damage done to the atmosphere. Although it made provision for the future it was unable to do much about the damage that had been caused in the past.
This novel also allows Deeba to use the UnGun as a weapon; the UnGun incorporates everything but bullets and shows that pollution can be fought successfully by repurposing and recycling rather than by creating more products that cannot be recycled without damage to the planet.
Girl Power
Deeba is an unlikely hero; she does things her own way. She is not the traditional super hero female type, and is not even the Chosen One in UnLondon. She is feisty, bold and definitely not afraid to take on a challenge which is what makes her the perfect poster girl for girl power. The other characters in the novel seem to defer to her, and wait for her to guide them in their battle, and they are also happy to have a female leading them rather than the other way around.
Zanna is also an example of girl power in that she is the Chosen One. Despite the fact that she does not do a very good job of fighting the Smog, she is game to try, and acquits herself well in terms of the courage that she shows. She is identified as the Shwazzy, the Chosen One, who has always been female. This shows that the society of UnLondon is more than ready to have a female at the helm.
