CEL problem

[edge_sg]

P0420 Catalyst system efficiency below threshold.

Any bro encounter this fault b4?
Mileage ard 200k.
CEL can be cleared though but will comes on sometimes.
CEL on at no fix distance or symptons.
But do notice that when driving town or traffic heavy area will light up.
Data shows O2 sensors working.
So is it the catalytic gone or the sensor issue?

Thanks..

[Honda Vezel 1.5RS]

Hi VTEC Lover, Did you manage to solve your CEL problem? If so, could you advise me?