THERE IS TOO MUCH TRAFFIC.( HOWEVER/ SINCE / SO / BUT ) THE AIR IS...

6. - KT HKII ANH 9 DAP AN MA TRAN 4 DE
KT HKII ANH 9 DAP AN MA TRAN 4 DE
6. There is too much traffic.( however/ since / so / but ) the air is polluted.