Scientists working in the Antarctica reported the depletion of ozone layer called ozone hole over the south pole of the Antarctica. This time the depletion was reported due to unique set of conditions. In the summer season the nitrogen dioxide and methane reacted with the chlorine monoxide and chlorine radicle respectively forming chlorine sinks thereby preventing the depletion of ozone.

ClO + NO₂ (g) → ClONO₂

Cl (g) + CH₄→ CH₃(g) + HCl (g)

ClONO₂ (g) +H2O → HOCl (g) + HNO₃

ClONO₂ (g) + HCl → Cl₂ (g) + HNO₃ (g)

Wherease in winters the formation of polar stratospheric clouds was observed over the entire Antarctic region. These clouds were reported to act as a surface over where the chlorine nitrate formed got hydrolysed to form hypochlorous acid. The acid thus formed reacted with hydrogen chloride to form molecular chlorine.

HOCl (g) → OH (g) Cl (g)

Cl + Cl Gives molecular chlorine

When the sunlight returned back in the spring it led to breaking up of clouds and HOCl and molecular chlorine gets photolysed by sunlight to form chlorine radicles as shown below:

Cl₂ (g) → 2 Cl

These chlorine radicles further caused the ozone depletion.