 The Altars of Forgiveness and of the Kings were subject to extensive cleaning and restorative work . To replace the lost portions on the Altar of Forgiveness , several paintings were added ; Escape from Egypt by Pereyns , The Divine Countenance and The Martyrdom of Saint Sebastian . The organs were dismantled with the pipes and inner workings sent to the Netherlands for repair , while the cases were restored by Mexican craftsmen with work lasting until 1977 . Reconstruction of the choir area began in 1979 using the same materials as existed before the fire . In addition , any statues in the towers that received more than 50 % damage from city pollution were taken out , with replicas created to replace them . Those with less damage were repaired . 
 The Altars of Forgiveness and of the Kings <a href='uninflect' title='1'><mark>were</mark></a> subject to extensive cleaning and restorative work . To replace the lost portions on the Altar of Forgiveness , several paintings <a href='uninflect' title='2'><mark>were</mark></a> added ; Escape from Egypt by Pereyns , The Divine Countenance and The Martyrdom of Saint Sebastian . The organs <a href='uninflect' title='3'><mark>were</mark></a> dismantled with the pipes and inner workings sent to the Netherlands for repair , while the cases <a href='uninflect' title='4'><mark>were</mark></a> restored by Mexican craftsmen with work lasting until 1977 . Reconstruction of the choir area began in 1979 using the same materials as existed before the fire . In addition , any statues in the towers <a href='null_relcl' title='5'><mark>that</mark></a>received more than 50 % damage from city pollution <a href='uninflect' title='6'><mark>were</mark></a> taken out , with replicas created to replace them . Those with less damage <a href='uninflect' title='7'><mark>were</mark></a> repaired . 
The Altars of Forgiveness and of the Kings was subject to extensive cleanin and restorative work . To replace the lost portions on da Altar of Forgiveness , several paintings was added ; Escape from Egypt by Pereyns , The Divine Countenance and The Martyrdom of Saint Sebastian . Tdaorgans was dismantled with thdaipes and inner workings sent to the Netherlands fa repair , while thedases was restored by Mexican craftsmen wid work lasting until 1977 . Reconstruction of the choir area began in 1979 using the dae materials as existed b4 the fire . In addition , any statues in the towers received more den 50 % damage from city pollution was taken out , ww/replicas created to replace them . Those witw/ss damage was repaired .