I wouldn't hazard a guess as to what's causing these blasts, some of them look like gas explosions, others definitely look more like explosives. Despite the image they project, and a couple thousand years of effort, China is a very diverse country. There are only about 1.5 million actual Party members to rule over the whole mess, which is why they need the police state to spy on and suppress citizens. They are always a couple bad harvests away from another revolution, their economy is a house of cards, albeit a very large house.