Not really secret, but very effective

I was overjoyed to hear I would be allowed to join an official "secret inspection" team. The idea was quite glamorous: A world of cloak and daggers and undercover James Bond-like activity. It didn't even occur to me that this once-in-a-lifetime game of shadows would end up being so humdrum and even monotonous.

The "secret checks" are actually conducted very publicly. We just drove around the city, looking for chimneys emitting colored smoke. When we found one, we established the identity of the owner, made notes and took photos. The only clandestine part of the process was ensuring that no one from the factories that owned the smokestacks spotted us.

The crucial element is the experience of the people conducting the checks. After decades in the field, Sui Xiaochan habitually looks for smoking chimneys and dirty rivers wherever she happens to be.