To produce a confining barrier preventing the movement of a pollutant in the ground and usable in the removal of the pollutant from ground water.

A fluid impermeable confining barrier is produced by a process forming a large fracture by the hydraulic fracturing of the ground, that is, a process performing hydraulic fracturing by injecting a compsn. selected from (i) an aq. soln. or dispersion of a material having gelling capacity, (ii) an aq. dispersion of a solid and (iii) a material capable of being coagulated by cooling or a soln./dispersion thereof through a well under pressure and a process holding the compsn. under pressure until a confining barrier substantially comprising the compsn. (i)-(iii) is formed.