 Walls are "captured" for fixed numbers of years, and graffiti over-painting is tantamount to political transgression.Generations of political graffiti artists have been at work on Kolkata's walls, producing slander, witty banter and limericks, caricatures and propaganda.However, such acts being clear cases of defacing private property, the Calcutta High Court ruled to ban political graffiti from private properties without express consent of the property owner.