The word "pollutings" is spelled with two "t"s because the stress falls on the second-to-last syllable, which is "tings." The first "t" is pronounced as a voiceless alveolar plosive /t/, and the second "t" is pronounced as a voiced alveolar plosive /d/. The vowel in the first syllable is pronounced as a short u sound /ʌ/, and the vowel in the second syllable is pronounced as a long i sound /aɪ/. The phonetic transcription of "pollutings" is /pəˈlutɪŋz/.