The civil aviation ministry today said it is "tough" to meet the 2019 deadline for starting operations at the much-awaited Navi Mumbai airport. It can be noted that state chief minister Devendra Fadnavis has repeatedly been saying that the work on the first phase of the Rs 16,700-crore Navi Mumbai International airport will be completed by the end of 2019. "I am happy to say that the work is going on schedule. It would be tough for us to do (to meet the 2019 deadline) that, but we will try. However, it will be tough," civil aviation secretary RN Choubey told reporters at the sixth US-India aviation summit here today. Significantly, the state assembly elections are also due for October next year. Choubey said that he had held extensive discussions with the stakeholders including the state government and the developer GVK group on the progress of the project last month. Prime Minister Narendra Modi had in February laid the foundation stone for the airport, which will give a breather to single-runway and slot-constrained Chattrapati Shivaji International airport in Mumbai. The new airport was proposed in 1997 as a secondary airport to meet the growing needs of Mumbai at an investment of Rs 3,000 crore. However, it received the government's approval only in 2007. The project got delayed due to the land acquisition issues and securing government permissions, including the environmental clearance. The airport project will be carried out on a public-private partnership model and Cidco has been mandated to execute the project. GVK group through its subsidiary, Mumbai International Airport (MIAL), holds 74 per cent stake in the Navi Mumbai International Airport (NMIAL), while Cidco holds the balance 26 per cent.