One of the first things I noticed when I moved to Shanghai was the abundance of bare baby buns. Why were these exposed fannies so prevalent? Because many parents do not use diapers here. Instead, children wear pants with a slit over the bum, allowing them to go to the bathroom when needed. Sometimes this will occur over a trash can but more often, it happens right on the sidewalk.
And in case you were wondering, the reason for the slit pants isn't entirely economical, though eliminating diaper spending certainly doesn't hurt. Many Chinese just prefer the split pants. I'm told it eliminates diaper rash and that it even helps to accelerate potty training. And any method that hastens the process by which humans start to use toilets is okay with me, because really, who wants to think about poo that much anyway?