From the geometric street grids of Anna Nagar to the banks of the Adyar River and beyond, Madras Transit is an urban portrait collection featuring 25 colour photographs from 10,000 ft above the sea level. These aerial photographs of Chennai, captured by Robert D Stephens are a commentary on the city, its history and its pollution levels. He is the Principal at RMA Architects and is passionate about the art of building and constructing beauty through visual, literary and cinematic imagery.

Here are 10 of the 25 images. Along with each image is a record of air pollution level, as measured by the Tamil Nadu Pollution Control Board. (SO2 stands for Sulphur Dioxide, NO2 stands for Nitrogen Dioxide and RSPM is Respirable Suspended Particulate Matter)

Venetian Vadapalani as on February 2015; SO2-21 ug/m3; NO2-28 ug/m3; RSPM - 68 ug/m3

Triplicane Assemblies as on July 2015; SO2-16 ug/m3; NO2-23 ug/m3; RSPM-150 ug/m3

The roads as on April 2015; SO2-015 ug/m3; NO2-18 ug/m3; RSPM-86 ug/m3

Kapaleeshwarar Temple as on June 2015; SO2-15 ug/m3; NO2-20 ug/m3; RSPM-65 ug/m3

Mount Road as on April 2015; SO2-16 ug/m3; NO2-21 ug/m3; RSPM-89 ug/m3

Madras Club as on June 2015; SO2-13 ug/m3; NO2-19 ug/m3; RSPM-31 ug/m3

MRC Nagar as on May 2015; SO2-14 ug/m3; NO2-18 ug/m3; RSPM-35 ug/m3

Georgetown Grid as on April 2015; SO2-14 ug/m3; NO2-18 ug/m3; RSPM-85 ug/m3

Race Course as on May 2015; SO2-15 ug/m3; NO2-17 ug/m3; RSPM-49 ug/m3

Kathipara Junction as on April 2015; SO2-16 ug/m3; NO2-20 ug/m3; RSPM-60 ug/m3

Madras Transit, in association with ARTISANS', exhibited these images in Chennai.