Since the UN climate change conference kicked off on Monday, security has been a hot topic among conference participants.

The two-week summit, which brings together more than 20,000 officials from nearly 200 countries and 10,000 non-governmental organizations, is taking place in Cancun, a coastal city in Mexico's eastern-most state, Quintana Roo, on the Yucatan Peninsula. It is also known as the Mexican Caribbean or the Mayan Riviera.

Security has been a key concern, especially with drug-related violence in the country, many locals say.

The Mexican government has deployed more than 6,000 police officers and troops to the resort city. There are also police patrols in the neighboring towns of Tulum, Playa del Carmen and Isla Mujeres, as well as at all resorts in the Mayan Riviera.

In addition, the Mexican navy is protecting the waters off Cancun, with more vessels patrolling the waters off Tulum, Playa del Carmen and the ports of Morelos and Aventuras.

But that's not all. Because it is a UN conference, UN security guards are also at conference venues. Twenty-five ambulances are on standby.

From Tuesday, some heads of states, many from Latin American countries, and senior UN officials including Secretary-General Ban Ki-moon will be at the summit.

Those who participated in last year's conference in Copenhagen, think the situation in Cancun gives less flexibility to protesters who created scenes inside and outside the Bella Center in Copenhagen and attracted enormous world attention. It is much quieter in Cancun.

But problems over logistics have been drawing most complaints since the start of the conference.

Mexico's Transport Ministry has designated a lane, known as the UN solo carril, to the Moon Palace main conference center, a beachfront complex, to ensure all daily shuttles which most participants depend on will run more efficiently.

Shuttles pick up delegates every 30 minutes from their hotels. While the pickups are on time, how long it takes to get to the destination may vary - ranging from 30 minutes to two hours, depending on traffic and from which hotel to which conference venue.