an ath ap ur am ▁and ▁ad jo ining ▁districts ▁These ▁districts ▁are ▁formally ▁known ▁as ▁Des ert ▁districts ▁of ▁T amil n adu . ▁ ▁Dis aster s ▁ ▁Flo ods ▁ 2 0 1 5 ▁South ▁Indian ▁flo ods ▁▁▁▁▁▁▁▁▁▁ ▁( ▁mostly ▁affected ▁areas ▁ch en na i , ▁kan ch ip ur am ▁and ▁c ud dal ore ) ▁Chen na i ▁received ▁ 1 , 0 4 9   mm ▁( 4 1 . 3   in ) ▁of ▁ra inf all ▁in ▁November , ▁the ▁highest ▁recorded ▁since ▁November ▁ 1 9 1 8 ▁when ▁ 1 , 0 8 8   mm ▁( 4 2 . 8   in ) ▁in ▁of ▁ra inf all ▁was ▁recorded .[ 2 4 ][ 2 5 ] ▁The ▁flo oding ▁in ▁Chen na i ▁city ▁was ▁described ▁as ▁the ▁worst ▁in ▁a ▁century .[ 2 6 ] ▁ ▁Cy cl ones ▁Cy clone ▁O ck hi ▁Cy clone ▁Th ane ▁Cy clone ▁J al ▁Cy clone ▁L ail a ▁ ▁Cy clone ▁V ard ah ▁ ▁Cy clone ▁Nad ah ▁Cy clone ▁G aja ▁cy clone ▁nel am ▁▁ 2 0 0 4 ▁Asian ▁t sun ami ▁dis aster ▁ ▁Dr ought ▁& ▁fam ine ▁ ▁Pol l ution ▁The ▁air ▁quality ▁of ▁industrial ▁areas ▁in ▁En n ore , ▁as ▁well ▁as ▁in ▁Po es ▁Garden ▁and ▁Bo at ▁Club ▁are ▁above ▁the ▁standards ▁pres cribed ▁by ▁the ▁environment ▁min istry , ▁according ▁to ▁a ▁report ▁by ▁Coast al