Your essay has some good and some not-so-good points, but the biggest feature is that it has 420 words. It’s too long! Very few people can write that many words successfully by hand in 40 minutes.  IELTS examiners and many textbooks warn that the longer the essay, the more errors. Try to write between 250 and 350 words.

You have also a very high average number of words in each sentence -  16.84. You need to get this down, by breaking up long sentences, checking punctuation and (the easiest solution) by adding some short sentences

You have a mix of some very good error-free sentences followed by some that stop the readers in their tracks. 

Watch out for detail which is not needed. You have sentences in there about the economic crisis and solar powered cars. Stick to the topic as closely as possible – those examples are not wrong, but they are not necessary.

Avoid Generalizations/Exaggeration

The growth of traffic and air pollution are the most concern problems of many countries.

Words like ‘most’ and ‘all’ are dangerous. Countries have many problems -  unemployment, political unrest, poverty, poor healthcare -  so is air pollution really the most important?

It’s easy to fix this problem in essays. Use ‘major’  instead of ‘most,' use 'many' or 'some' instead of all, use 'many' instead of 'most.' Let's make the sentence more specific, as well:

Air pollution and traffic congestion are major problems in many cities.

Specify

This essay will discuss both sides of the opinion, and mention some measures that I think can be efficient.

This sentence could be used in a million essays. Make every sentence related to the topic.

This essay will discuss the advantages and disadvantages of increasing fuel prices, and mention some alternatives such as energy-efficient public transport and even free bicycles!

You wrote:

On the one hand, there are two benefits from this solution.

Avoid pronouns in the first sentence of  a new paragraph. What is ‘this solution’? Make every sentence specific to the topic

Increasing the price of fuel has two main advantages.

Word Choice/Word Form/Usage

• First, it can decline the rise of vehicles. → it can slow/reduce/halt the increase in the number of vehicles.
• the economical crisis → the economic crisis
• rising the price of petrol provides disadvantage as well  →  raising the price of petrol
• It can be harmful for the traffic industries. → it can be harmful for the car manufacturers/ companies /producers
• As the result of this, many companies will have difficulties in purchasing vehicles. → As a result of this, many companies will have difficulty selling vehicles.

Punctuation

Leave commas out if in doubt.

• Even though, many producers…. → even though many producers

Don’t use commas to join what should be separate sentences

• This has been applied in China, due to the second largest population in the world, it's public transport can not serve all the people.

This has been applied in China. Because it has the second largest population in the world, its public transport cannot serve all the people.  OR

China’s public transport cannot serve all its huge population. As a result…

Avoid extra details

You have a sentence about the economic crisis which is interesting but not directly relevant. Let’s leave it out. (Look at Band 5 of the IELTS Task 2 Descriptors under Task Response)

On the one hand, there are two benefits from this solution. First, it can decline the rise of vehicles. Living standard is improving, and many people are able to have their own cars or motorbikes. However, the economical crisis has occurred which forces them consider about their spending. Therefore, people are more deliberate not only about buying cars or motorbikes but also driving them because of petrol's price. Second, this measure can really solve air pollution problem. More and more people willing to use public transport in order to saving money so the carbon dioxide emissions can be reduced, which is one of the main reasons of air pollution. (109 words)

Shorten and omit unnecessary details

Here’s a rewrite of the same paragraph - Paragraph 2  - in just 52 words.

Increasing the price of fuel has two main advantages. First it can reduce the number of new vehicles.  If fuel prices go up, more people will reconsider buying cars or motorbikes. Secondly, this measure can really help to solve air pollution.  More people using public transport would mean less carbon emissions and a cleaner environment. (52 words)

Repeated Subject

You wrote:

For fear of not having enough money to pay for petrol, especially the commoner, they will reconsider about buying them.

Shorten and simplify:

Ordinary people will not buy them because of the cost of fuel.

You have 194 words in Paragraph 3. This is very long.

Here’s a shorter rewrite of Paragraph 3 in 130 words:

On the other hand, increasing the price of petrol can have some disadvantages. It can harm car manufacturers.  People will be less likely to buy new cars if they are worried about high fuel costs. Some car producers have introduced cars using alternative energy sources, but these are too expensive and only suitable for the rich. However, there are two methods that I think might be effective. Firstly, governments should provide public transport systems which use renewable sources, such as solar energy, electricity or gases. For example, in Melbourne, locals and visitors use an electric bus system which is cheap and comfortable. Another strategy is to provide bicycles for rent.  In many Chinese cities, the government provides bicycles, and these are used by many for short journeys or for exercise. (130 words)

I like your conclusion.

Overall, tnduong, just try to keep your paragraphs shorter by eliminating unnecessary details and thinking about how to make your sentences shorter. Looking forward to seeing some shorter essays here!

Welcome to writefix  - good to have you here. I hope some people will add one or two comments for you. I have some ready, but I'm waiting to see what other people say first.  

In the meantime, why don't you write a sentence or two on Rebecca's essay (she's new too!) or on Yokama's new IELTS topic?

If you like how a person writes, you can click on their photograph or icon to find more. Most people don't seem to add photos, though!  :(

The growth of traffic and air pollution are the most concern problems of many countries. Many solutions have been introduced, and one of them is the increase of petrol's price. In my opinion, I partially agree with this view. This essay will discuss both sides of the opinion, and mention some measures that I think can be efficient.

On the one hand, there are two benefits from this solution. First, it can decline the rise of vehicles. Living standard is improving, and many people are able to have their own cars or motorbikes. However, the economical crisis has occurred which forces them consider about their spending. Therefore, people are more deliberate not only about buying cars or motorbikes but also driving them because of petrol's price. Second, this measure can really solve air pollution problem. More and more people willing to use public transport in order to saving money so the carbon dioxide emissions can be reduced, which is one of the main reasons of air pollution.

On the other hand, rising the price of petrol provides disadvantage as well. It can be harmful for the traffic industries. For fear of not having enough money to pay for petrol, especially the commoner, they will reconsider about buying them. As the result of this, many companies will have difficulties in purchasing vehicles. Even though, many producers introduced cars using renewable energies, they are too expensive for most customers, and only suitable for the rich.

However, there are two methods that I think might be effective. Firstly, governments should provide public transport systems which use renewable sources, such as solar energy, electricity or gases. For example, in Melbourne (Australia), there is an electrical bus system which has been used by the local people and many visitors because it is cheap and comfortable. Another method is bicycles for rent. This has been applied in China, due to the second largest population in the world, it's public transport can not serve all the people. Therefore, the government provides bicycles, and it became the best choice for many young and old people whose schools or companies are near their houses or they want to do exercises.

In conclusion, perhaps increasing the price of petrol can reduce the rise of traffic, especially in today crisis, and solve pollution problems. However, it can make damage to the vehicle industries and other businesses involved in it. So governments and people should seek better solutions that not only help the environment but also do not have negative influences on economy.