Replace 'is' with 'are'. Although 'police' appears singular, yet it is used in 'plural' sense.
becoming more and more inactive.
**You do not need to add “s” “es” to make them plural.
|Cattle, People, Police, Gentry, Peasantry, Electorate, Nobility, Poultry, Riches, Odds Arms, Bellows, Fetters, Pincers, Tongs, Sheers, Scissors Trousers, Pants, Pantaloons, Trappings, Socks, Shorts, Stockings Clergy, Folk, Mankind, Vermin, Public, Premises, Alms, Goods, Surroundings|
|Incorrect:||Peoples should be loyal to the nation.|
|Correct:||People should be loyal to the nation.|