Table 5.

ZA unit root test

	At level I(0)		First difference I(1)		Decision
	Intercept & trend	Break-date	Intercept & trend	Break-date
GDP	− 2.8836	1994	− 7.8407*	1983	I(1)
CO2	− 3.8751	1993	− 8.6482*	1998	I(1)
EC	− 4.2704	1991	− 7.9482*	1984	I(1)
GCF	− 6.4665*	1998	− 7.0113*	1997	I(0), I(1)
URB	− 5.2474**	1986	− 5.7052*	1996	I(0), I(1)

Note: 1% and 5% level of significance is illustrated by * and ** respectively