Too much old money

Money seems often to be a problem, most commonly because people feel they don't have enough. In an article, 'Withdaw false cases against JNU students' in The Daily Star on Wednesday, 11 February 2008 it was evident that there can sometimes be too much, too.
Agitated students from Jagannath University demonstrated for eight issues of which the last was a "demanded [for] removal of the Bangladesh Bank branch from the campus which pollutes air by burning old currency notes beside the campus."
I am sure there is a good explanation for this, but it is hard to imagine that there is that much old money to burn. You can read the entire article by clicking on the headline above.
If you have a better explanation, please leave a comment on this blog.