Steppe Gull, Larus barabensis

Adult, February

 Yamuna River, New Delhi, India

Judged to be cachinnans rather than barabensis as upperparts fairly pale and it has a strong bill. P10 has a large white mirror separated by a narrow band from white tip, P9 has a small roundish white mirror which just reaches the edges of the feather - this can also be seen on the backlight far side wing of the bird in the last picture.