Complex sentence: His health was damaged by mustard gas, so he emigrated to New Zealand in 1927 where he lived in Hastings (serving on the Hastings Borough Council and Napier Harbour Board), and then to Auckland in 1931.
Split into simpler sentences: His health was damaged by mustard gas, so he emigrated to New Zealand in 1927 where he lived in Hastings. Lyon served on the Hastings Borough Council and Napier Harbour Board before moving to Auckland in 1931.