China has been laying new roads and improving its overall infrastructure along the nearly 4,000 km long border with India.
Earlier this month, defence minister Nirmala Sitharaman had said China has undertaken construction of helipads, sentry posts and trenches for its army personnel near Doklam.
Sources said China has been keeping its troops in north Doklam and significantly ramping up its infrastructure in the disputed area.
In January, Army Chief Gen Bipin Rawat had said the time had come for India to shift its focus from borders with Pakistan to the frontier with China, indicating the seriousness of the situation.