July 13 Leaving Linyi we came across a canal so polluted it looks like thinned-down black enamel paint. It gave off an extremely foul, chemical odour ... A young man of about 20 came over. 'Five or six years ago I used to swim in this river,' he said. 'And we ate crayfish and fish from it.' I commented that it looked like oil. 'It is oil. It's coming from a nearby petroleum company.' July 16, on Shandong-Hebei border We encountered the foulest air of our trip through China, and that's saying something. July 17 A worker at the visa department of the Cangzhou Public Security Bureau says: ''We cannot give you a visa here. You must go to Dezhou , in Shandong .' That's 120km back. July 18 Dezhou Public Security Bureau official says the only person who can put a visa in my passport is away till the end of next week. July 21, Jinan Finally, I got the visa; a special one, they said. It would only last 10 days, but it would be enough to last until our arrival in Tianjin . July 22 We can restart our walk, but first we have to take a taxi back to Cangzhou, which is on our walking route ... A few kilometres down the road a motor bike appears out of nowhere. The driver slams on the brakes ... Bang! The guy disappears. We get out. He's lying jammed between the car and a guard rail ... His leg is broken. Eventually a police car comes along. He looks, but does not stop. 'Why is he not stopping?' I ask. 'He's not traffic police,' is the reply.