『Abstract
　To understand the effect of monsoon and marine environment on the colour of building stones of the ‘Gateway of India’ monument, 133 samples from different areas were assessed. Colour changes were evaluated using Microflash 200d colour spectrophotometer over a period of 1 year. The alteration in the stones effecting the colour change was studied by petrographic thin section, which shows that the colour change is associated with weathering of the feldspars.

Keywords: Monument; Colour measurement; Stone degradation; Petrograph; Colour change』

Introduction
Historical background
Research methodology
Colour-measurement technique
Results and discussion
Conclusions
Acknowledgements
References