The owner of any interest in the dominant heritage, or the occupier of such heritage, may institute a suit for compensation for the disturbance of the easement or of any right accessory thereto; provided that the disturbance has actually caused substantial damage to the plaintiff.
     Explanation I.--The doing of any act likely to injure the plaintiff by affecting the evidence of the easement, or by materially diminishing the value of the dominant heritage, is substantial damage within the meaning of this section and section 34.
     Explanation II.--Where the easement disturbed is a right to the free passage of light passing to the openings in a house, no damage is substantial within the meaning of this section unless it falls within the first Explanation, or interferes materially with the physical comfort of the plaintiff, or prevents him from carrying on his accustomed business in the dominant heritage as beneficially as he had done previous to instituting the suit.
     Explanation III.--Where the easement disturbed is a right to the free passage of air to the openings in a house, damage is substantial within the meaning of this section if it interferes materially with the physical comfort of the plaintiff, though it is not injurious to his health.
                                                  Illustration
         (a) A places a permanent obstruction in a path over which B, as tenant of C's house, has a right of way. This is substantial damage to C, for it may affect the evidence of his reversionary right to the easement.
         (b) A, as owner of a house, has a right to walk along one side of B’'s house. B builds a verandah overhanging the way about ten feet from the ground, and so as not to occasion any inconvenience to foot-passengers using the way. This is not substantial damage to A.