quimcunx
imprimeo, lamino, distribuo
It's certainly impressive what Kerala has managed but you can't ignore various significant differences between Kerala and the UK.
The population is about 35 million (about half the UK population).
It looks like they receive about 1 million international arrivals a year.
Compare that with just Heathrow airport, which sees about 75 million international arrivals a year.
If the UK had stopped international arrivals at around the same point as Kerala had done, who knows how many cases would already have been here - might have been 100x the number that Kerala then managed to get on top of.
cities/states/countries are all different with different challenges. If the figures had been reversed what reasons would people posit for that? If we demanded to know why Kerala did so badly compared to the UK? What significant differences couldn't we ignore then? Well the UK is very very rich, Kerala is many many times poorer. Kerala is far more densely populated than the UK. Imagine if they'd had to isolate in overcrowded unsanitary houses for weeks and months instead of palatial houses and flats like they did in the UK? Kerala doesn't have a natural border it can defend like the UK did. etc. etc.