  Graph burning runs on discrete time steps. The aim is to burn all the
vertices in a given graph in the least number of time steps. This number is
known to be the burning number of the graph. The spread of social influence, an
alarm, or a social contagion can be modeled using graph burning. The less the
burning number, the faster the spread.
  Optimal burning of general graphs is NP-Hard. There is a 3-approximation
algorithm to burn general graphs where as better approximation factors are
there for many sub classes. Here we study burning of grids; provide a lower
bound for burning arbitrary grids and a 2-approximation algorithm for burning
square grids. On the other hand, burning path forests, spider graphs, and trees
with maximum degree three is already known to be NP-Complete. In this article
we show burning problem to be NP-Complete on connected interval graphs,
permutation graphs and several other geometric graph classes as corollaries.
