濁(にご)るto become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks

工場(こうじょう)からの排水(はいすい)で川(かわ)の水(みず)が濁(にご)る。

The river water becomes murky due to the wastewater from the factory. {to become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks}

風邪(かぜ)を引(ひ)いた。濁(にご)った声(こえ)になってしまった。

I caught a cold. My voice has become hoarse. {to become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks}

車(くるま)やトラックからのガスで空気(くうき)が濁(にご)っています。

The air is polluted with gas from cars and trucks. {to become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks}

この字(じ)には濁点(だくてん)がついているので、濁(にご)って読(よ)むと考(かんが)えられます。

This character has a voicing mark, so it is considered to be read as a voiced sound. {to become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks}

濁(にご)っている部屋(へや)の空気(くうき)を綺麗(きれい)にするために、空気(くうき)清浄(せいじょう)機(き)を買(か)いました。

I bought an air purifier to clean the air in the murky room. {to become muddy, to become cloudy, to get impure (of a liquid, gas, etc.), to become dull (of a sound, color, etc.), to become hoarse, to become impure (of a heart, society, etc.), to be corrupted, to be polluted, to become voiced, to add voiced consonant marks}