Simplify the following text for a Grade 15 native English-speaking person.
Original: However , some of the counties established by the Act were entirely new , such as Avon , Cleveland , Cumbria , Hereford and Worcester , and Humberside , along with the new metropolitan counties of Greater Manchester , Merseyside , South Yorkshire , Tyne and Wear , West Midlands and West Yorkshire ; based on the major conurbations .
Simplified: Some of the counties established by the Act were entirely new , such as Avon , Cleveland , Cumbria , Hereford and Worcester , and Humberside , along with the new metropolitan counties of Greater Manchester , Merseyside , South Yorkshire , Tyne and Wear , West Midlands , and West Yorkshire .