Following a welcoming ceremony in the country's eastern city Sophie, 48, met with children from Future Hope, an NGO that provides homes, schooling and medical care to come of Kolkata's most vulnerable children.
Dressed in blue and white patterned trousers and a black shirt, the mother-of-two was presented with a bouquet by the excited children and planted a tree in the grounds of the ITC Sonar Kolkata Hotel.
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The Countess chatted to children who have been helped by the charity, which was founded by British-born Tim Grandage, and fed koi carp in the garden's pond.
Prince Edward's wife is currently undertaking a week-long trip to India and Qatar with the sight-saving charity ORBIS.
On Thursday Sophie will visit ORBIS' Flying Eye Hospital, a DC-10 plane that performs surgery on those living in poverty-stricken areas, where she will watch cataract surgery and try her hand at the operation using a surgery simulator.
The Countess will visit a partner hospital where she will speak to patients and hear from local trainees before giving a speech at a medical training symposium.
Sophie will then journey to Qatar to meet with the donors who support ORBIS in India and Bangladesh.