UK prime minister Theresa May made her first major trade mission to India this week, where discussions centred around immigration and the outline of any future trade deal with the country remained sketchy.

The three-day visit included a technology conference and a meeting between May and Indian prime minister  Narendra Modi. Modi pushed for a more flexible visa system for Indians as part of any trade deal with India – a request that May could not support since limitations to the number of immigrants  to the UK was a major factor in the country’s decision to leave the European Union earlier this year.

May extended measures that would help wealthy Indians get special treatment at the point of entering the UK , but any further concessions would only follow India taking action on Indians who are thought to have overstayed their visas in the UK.

At a press conference with Modi, May highlighted co-operation for urban development and said the two countries had agreed on a partnership that would “unlock opportunities worth £2bn for UK businesses in the next 5 years” to help develop smart cities in the Indian state of Madhya Pradesh.

“Alongside this, the UK has agreed to invest £120mn in a joint fund that will lever private sector investment from the City of London to finance Indian infrastructure,” she said, adding that the potential for commercial opportunities within these areas was “huge” and that, “on this visit alone, more than £1bn of business deals will be signed”.

In July, India launched the first rupee-denominated “masala” bond in London to raise over £900mn of financing for infrastructure projects. May said a further four bonds with a total value of £600mn will be issued in London in the next three months.

May was accompanied by the UK secretary of state for international trade, Liam Fox, and the trade minister Greg Hands.The trip also included 33 British business figures, including chairman of Standard Chartered John Peace and chairman of Standard Life Gerry Grimstone.

Technically, the UK cannot make any new trade deals until it has left the EU, but ministers are actively trying to muster up support for future agreements with key countries, mainly in the commonwealth, including Australia, Canada and India.

India has been a tough nut to crack for even the EU, which has been struggling to make a deal with the country for several years. Visa laws for businesses, students and tourists are at the heart of the issue in EU debates also.