Dinitrogen is a robust compound, but reacts at hig altitude to form oxides. The oxide of nitrogen the can damage plant leaves and retard photosynthes is

Dinitrogen and dioxygen are the main constituents of air. These gases do not react with each other at a normal temperature. At high altitudes when lightning strikes, they combine to form oxides of nitrogen. 

${\mathrm{N}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{NO}\left(\mathrm{g}\right)$

NO reacts instantly with oxygen to give NO₂

$2\mathrm{NO}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$

Rate of production of NO₂ is faster when nitric oxide reacts with ozone in the stratosphere

The irritant red haze in the traffic and congested places is due to oxides of nitrogen. Higher concentrations of NO₂ damage the leaves of plants and retard the rate of photosynthesis. It is toxic to living tissues also