Read something new this week!!

I happened to read a book on geological wonders of Alberta and on it i happened to see something called sinkholes.. Its given as occuring in Wood Buffalo National Park. That got me searching about sinkholes and saw quite a few webpages on the same. Truly frightening point to note is sinkholes can be man made too, i mean made by man due to blunders by man.. For e.g. In pennysylvania, it seems the underground sewage system is so bad that there are lots of formations of sinkholes.. That got me thinking.. If in such a advanced country,the sewage system is outdated,what about sewage systems in India where they dont replace at all.. Whats the possibility of a sinkhole forming right in the middle of very own Mount Rd in Chennai? Thats definitely a possibility..But possibly the terrain is so tenacious that it withstands human blunders too?? still wondering!!