Hi. I am pasting a sample of the date of I am working with:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str2 state double year int year_law str3 neigh_state
"AZ" 1988 1987 "CT"
"AZ" 1988 1987 "DE"
"AZ" 1988 1987 "GA"
"AZ" 1988 1987 "IA"
"AZ" 1989 1987 "CT"
"AZ" 1989 1987 "DE"
"AZ" 1989 1987 "GA"
"AZ" 1989 1987 "IA"
"AZ" 1990 1987 "CT"
"AZ" 1990 1987 "DE"
"AZ" 1990 1987 "GA"
"AZ" 1990 1987 "IA"
"AZ" 1991 1987 "CT"
"AZ" 1991 1987 "DE"
"AZ" 1991 1987 "GA"
"AZ" 1991 1987 "IA"
"AZ" 1992 1987 "CT"
"AZ" 1992 1987 "DE"
"AZ" 1992 1987 "GA"
"AZ" 1992 1987 "IA"
"AZ" 1993 1987 "CT"
"AZ" 1993 1987 "DE"
"AZ" 1993 1987 "GA"
"AZ" 1993 1987 "IA"
"CT" 1989 1989 "MA"
"CT" 1989 1989 "RI"
"CT" 1989 1989 "NY"
"CT" 1990 1989 "MA"
"CT" 1990 1989 "RI"
"CT" 1990 1989 "NY"
"CT" 1991 1989 "MA"
"CT" 1991 1989 "RI"
"CT" 1991 1989 "NY"
"CT" 1992 1989 "MA"
"CT" 1992 1989 "RI"
"CT" 1992 1989 "NY"
"CT" 1993 1989 "MA"
"CT" 1993 1989 "RI"
"CT" 1993 1989 "NY"
"DE" 1988 1988 "PA"
"DE" 1988 1988 "NJ"
"DE" 1988 1988 "MD"
"DE" 1989 1988 "PA"
"DE" 1989 1988 "NJ"
"DE" 1989 1988 "MD"
"DE" 1990 1988 "PA"
"DE" 1990 1988 "NJ"
"DE" 1990 1988 "MD"
"DE" 1991 1988 "PA"
"DE" 1991 1988 "NJ"
"DE" 1991 1988 "MD"
"DE" 1992 1988 "PA"
"DE" 1992 1988 "NJ"
"DE" 1992 1988 "MD"
"DE" 1993 1988 "PA"
"DE" 1993 1988 "NJ"
"DE" 1993 1988 "MD"
"GA" 1988 1988 "NC"
"GA" 1988 1988 "SC"
"GA" 1988 1988 "FL"
"GA" 1988 1988 "AL"
"GA" 1988 1988 "TN"
"GA" 1989 1988 "NC"
"GA" 1989 1988 "SC"
"GA" 1989 1988 "FL"
"GA" 1989 1988 "AL"
"GA" 1989 1988 "TN"
"GA" 1990 1988 "NC"
"GA" 1990 1988 "SC"
"GA" 1990 1988 "FL"
"GA" 1990 1988 "AL"
"GA" 1990 1988 "TN"
"GA" 1991 1988 "NC"
"GA" 1991 1988 "SC"
"GA" 1991 1988 "FL"
"GA" 1991 1988 "AL"
"GA" 1991 1988 "TN"
"GA" 1992 1988 "NC"
"GA" 1992 1988 "SC"
"GA" 1992 1988 "FL"
"GA" 1992 1988 "AL"
"GA" 1992 1988 "TN"
"GA" 1993 1988 "NC"
"GA" 1993 1988 "SC"
"GA" 1993 1988 "FL"
"GA" 1993 1988 "AL"
"GA" 1993 1988 "TN"
end

I basically want to drop observations if for any state e.g AZ, year>=year_law and for the neigh_state e.g CT, the year >=year_law i.e. I want to drop the observations for a state and neigh_state when the two conditions hold simultaneously (is true at the same time). I can do this by creating dummy variables and drop when the dummy variables for two states is 1 at the same time but the method is quiet time consuming. Just wondering if there is some efficient way of doing this. Thank You.