create table member_example(dist1  varchar2(20)); 

insert all 
into member_example values ('HYD')
into member_example values ('VZG')
into member_example values ('VJD')
into member_example values ('TRP')
into member_example values ('WGL')
into member_example values ('MBN')
into member_example values ('RGR')
into member_example values ('MDK')
select * from dual;

declare 
type city_type_list is table of  varchar2(20);
list1 city_type_list;
cnt number ;
begin 
list1  := city_type_list('HYD','MDK');
select count(distinct dist1)
  into cnt
  from member_example
 --where dist1 member of list1
 ;
 dbms_output.put_line('count  '||cnt);
end;

SQL> create or replace
  2    type city_type_list is table of  varchar2(20);
  3  /

Type created.

SQL> set serveroutput on
SQL> declare
  2      list1 city_type_list := city_type_list('HYD','MDK');
  3      cnt number;
  4  begin
  5      select count(distinct dist1)
  6        into cnt
  7        from member_example
  8        where dist1 member of list1;
  9      dbms_output.put_line('count  '||cnt);
 10  end;
 11  /
count  2

PL/SQL procedure successfully completed.

SQL>