7 9 ▁▁ ▁The ▁Se as l ug ▁forum ▁: ▁max act e on ▁han co cki ▁ ▁Category : Act e on idae ▁Category : G ast rop ods ▁of ▁New ▁Zealand ▁Category : G ast rop ods ▁described ▁in ▁ 1 9 7 1 <0x0A> </s> ▁In ▁response ▁to ▁concerns ▁that ▁vol can ic ▁ash ▁e ject ed ▁during ▁the ▁ 2 0 1 0 ▁er u ptions ▁of ▁E y ja f j alla jö k ull ▁in ▁I cel and ▁would ▁damage ▁aircraft ▁engines , ▁the ▁controlled ▁air space ▁of ▁many ▁European ▁countries ▁was ▁closed ▁to ▁instrument ▁flight ▁rules ▁traffic , ▁resulting ▁in ▁what ▁at ▁the ▁time ▁was ▁the ▁largest ▁air - tra ffic ▁shut - down ▁since ▁World ▁War ▁II . ▁The ▁clos ures ▁caused ▁millions ▁of ▁passengers ▁to ▁be ▁str and ed ▁not ▁only ▁in ▁Europe , ▁but ▁across ▁the ▁world . ▁With ▁large ▁parts ▁of ▁European ▁air space ▁closed ▁to ▁air ▁traffic , ▁many ▁more ▁countries ▁were ▁affected ▁as ▁fl ights ▁to , ▁from , ▁and ▁over ▁Europe ▁were ▁cancel led . ▁ ▁After ▁an ▁initial ▁un inter rupted ▁shut down ▁over ▁much ▁of ▁northern ▁Europe ▁from ▁ 1 5 ▁to ▁ 2 3 ▁April , ▁air space ▁was ▁closed ▁inter mitt ently ▁in ▁different ▁parts ▁of ▁Europe ▁in ▁the ▁following ▁weeks , ▁as ▁the ▁path ▁of ▁the ▁ash ▁cloud ▁was ▁track ed . ▁The ▁ash ▁cloud ▁caused ▁further ▁dis ru ptions ▁to ▁air ▁travel ▁operations ▁in ▁Scotland ▁and ▁Ireland ▁on ▁ 4 ▁and ▁ 5